What is the place of magnesium in the treatment of migraine?

Magnesium is a rather understated metal which however plays such a significant role in health. This should not be surprising as it is the eighth most common metal in the Earth’s crust, and the fourth most abundant mineral in the human body. Explaining why magnesium is so central to health, Uwe Gröber and colleagues, in their paper titled Magnesium in prevention and therapy, point out that this underrated element is a cofactor in more than 300 enzyme systems which regulate such diverse biochemical reactions ranging from protein synthesis to neuromuscular transmission.

By Maral10Own work, Public Domain, Link

With such an important physiological function, it is alarming that the body can very easily run out of magnesium. But this is exactly what Gröber and colleagues demonstrated in their paper, which was incidentally published in the journal, Nutrients, in 2015; they showed that magnesium deficiency can result from a myriad of medical disorders such as alcoholism, malabsorption, endocrine disorders, chronic kidney diseases, and dialysis, or from the use of drugs such as antibiotics, chemotherapeutic agents, diuretics, and proton pump inhibitors.

CC BY 3.0, Link

Because of its diverse and important role, magnesium deficiency doesn’t lie down quietly in the corner and mope; rather it screams out in many tongues. Low magnesium therefore presents with symptoms such as lethargy, vomiting, fatigue, cramps, tremor, carpopedal spasm, tetany, seizures, and cardiac arrhythmias. Even more astonishing is the list of disorders that may be triggered by magnesium deficiency, from asthma, diabetes, hypertension, and osteoporosis, to stroke, attention deficit hyperactivity disorder (ADHD), Alzheimer’s disease, of all things, and of course migraine. Obstetricians will of course remind us of the indispensability of magnesium for eclampsia.

By LeiemOwn work, CC BY-SA 4.0, Link

With the foregoing in the background, it is easy to understand why researchers have thoroughly investigated the possible place of magnesium in the treatment of migraine. Exploring its prophylactic role, for example, Hsiao-Yean Chiu and colleagues touted the virtues of magnesium in their paper titled Effects of intravenous and oral magnesium on reducing migraine: a meta-analysis of randomized controlled trials. Publishing in the journal Pain Physician in 2016, the authors reviewed 10 key studies, with a combined number of 789 subjects, which assessed the ability of magnesium to prevent migraine, and they concluded that “oral magnesium significantly alleviated the frequency and intensity of migraine“. The authors felt confident enough in their findings to recommend oral magnesium as a part of a “multimodal approach to reduce migraine”.

By KulmalukkoOwn work, CC BY-SA 3.0, Link

Even more authoritative about the role of magnesium in migraine prophylaxis is the conclusion of the systematic review published in the journal Headache in 2017 titled Magnesium in migraine prophylaxis-is there an evidence-based rationale? a systematic review. The authors, Alexander von Luckner and Franz Riederer, found grade C, or possibly effective, evidence in support of the preventative role of magnesium in migraine. Going further, Charly Gaul and colleagues, publishing in the Journal of Headache and Pain in 2015, reported that adding riboflavin and coenzyme Q10 significantly increased the beneficial effect of magnesium.

Magnesium. fdecomite on Flickr. https://www.flickr.com/photos/fdecomite/6257573610

There is however a dampener to the celebrity status of magnesium in the migraine prophylaxis saga:  some reports simply found insufficient evidence for it. One such paper, published in the journal Cephalalgia in 2014 is titled An evidence-based review of oral magnesium supplementation in the preventive treatment of migraine. The authors, Levi Teigen and Christopher Boesy, reviewed 16 relevant studies and concluded that “the strength of evidence supporting oral magnesium supplementation is limited at this time“. But even then, they appreciate that absence of evidence is not the evidence of absence. They therefore did not dismiss the potential benefit of magnesium in migraine, and had no objection to migraineurs supplementing their dietary magnesium intake. As this paper was published in 2014, a lot has clearly passed under the bridge since then.

By Ben MillsOwn work, Public Domain, Link
Magnesium in the acute treatment of migraine has also been under scrutiny, and one such searchlight was shone by Hsiao-Yean Chiu and colleagues in their paper cited above. After reviewing 11 relevant studies comprising 948 subjects, they found that “intravenous magnesium significantly relieved acute migraine“. It is reassuring that two older papers also came to the same conclusion; the first, by ME Bigal and colleagues, was published in the journal Cephalalgia in 2002, and the second, by Şeref Demirkaya and colleagues, is reported in the journal Headache in 2004. Both papers revealed that 1000mg of magnesium sulfate intravenously was effective in aborting acute migraine attacks, especially if the attacks are associated with auras. Furthermore, writing in the journal Clinical Neurology and Neurosurgery in 2019, Fanny Xu and colleagues found that magnesium is effective even in status migrainosus, the most pernicious form of acute migraine.
By LoethlinOwn work, CC BY-SA 4.0, Link

But, as you guessed, the verdict on the benefit of magnesium in acute migraine is far from unanimous. For example, Y Cete and colleagues, publishing their case series of emergency department patients in the journal Cephalagia in 2005, reported that magnesium is no better than placebo for acute migraine. Furthermore, Hyun Choi and Nandita Parmar in their meta-analysis, published in the European Journal of Emergency Medicine in 2014, said intravenous magnesium “failed to demonstrate a beneficial effect” in acute migraine. Arpad Pardutz and Laszlo Vecsei, commenting in the Journal of Neural Transmission in 2012, even discouraged the use of magnesium because there are more effective treatment options.

By Pixelmaniac pictures (Leave a reply) – Own work, CC0, Link

Why are there such conflicting conclusions about the value of magnesium in acute migraine? One answer may lie in the almost prehistoric observation by Alexander Mauksop and colleagues; writing way back in 1996, in the journal Headache, they suggested that only a subset of migraine sufferers are susceptible to low magnesium levels. The authors go further to argue that low magnesium may be a trigger, not just for migraine, but for tension type headaches and cluster headaches; they therefore recommended that magnesium levels should be assessed in patients presenting with significant headaches, whatever the cause.

By 2×910Own work, CC BY-SA 4.0, Link

In conclusion, the evidence for the use of oral magnesium in migraine prophylaxis justifies its clinical use. The evidence for the use of intravenous magnesium for acute migraine is however less clear-cut, and future studies may help to clarify the ambiguity. In the meantime, it may be worth checking magnesium levels when a migraine attack defies conventional treatment: a top-up might just make the difference. And for the researchers, it may be time to look more closely at precision migraine medicine – it might just help to define those migraine sufferers who will benefit from that magic shot of magnesium.

By Warut RoonguthaiOwn work, CC BY-SA 3.0, Link

The emerging influential role of microglia in neurology

By GerryShawOwn work, CC BY-SA 3.0, Link

The most important clinical fallout of dysfunctional microglia appears to be the emergence of dementia. It is indeed speculated that microglia may hold the key to stopping the notorious Alzheimer’s disease (AD). This is because microglia seem to play a role in eliminating the amyloid plaques which are thought to contribute to the disease process. Experiments suggest that there is excessive microglial activation in AD, and these supercharged microglia destructively eat up’ synapses, the all-important junctions where nerve cells communicate with each other. It is also relevant that microglial activation is particularly prominent in the hippocampus, a structure critical for memory formation. Because synaptic loss is such a key feature of AD, it is hoped that a better understanding of microglial function may lead to therapeutic tools that modulate AD microglial activation.

Microglial cells and photoreceptors. NIH Image Gallery on Flickr. https://www.flickr.com/photos/nihgov/46571706425

Microglial activation also seems to play a role in another prominent neurodegenerative disease, Parkinson’s disease (PD). It is also speculated that microglia are activated in PD as a response to environmental triggers, and the activated microglia cause neuronal damage by producing toxic substances. Because this is presumably an inflammatory process, there is the hope that a better understanding of the process will open up new therapeutic possibilities.

Microglia. NIH Image Gallery on FLickr. https://www.flickr.com/photos/nihgov/42301918151

Another disorder in which microglia may play a pathogenetic role is frontotemporal dementia (FTD) in which chronic microglial activation has been reported. It is significant that the microglial activation is most evident in the frontal cortex as this correlates with the behavioural and speech disorders which characterise FTD. More intriguingly, the activated microglia seem to express the progranulin (PGRN) gene mutations that are known to be associated with FTD. Enough clues one might say.

By Mary AntipovaOwn work, CC BY 4.0, Link

The reach of microglial dysfunction however goes way beyond the big three of AD, PD, and FTD. For example, microglia are acutely activated in traumatic brain injury (TBI), and this may be responsible for the damage that results from this. Microglia also appear to be relevant in cerebrovascular disorders because microglial activation has been reported in ischaemic stroke and in haemorrhagic stroke. And the cherry on top is surely the report that microglia play a role in prion disorders. It may well turn out that neuroscientists are just opening up the microglial can of worms.

Abraçada de microglia Patricia Bogdanov-Cristina Sola-Joel Sampedro- Marta Valeri. Vall d’Hebron Institut de Recerca VHIR on Flickr. https://www.flickr.com/photos/vhir/31615774702

***

Want to find out more on microglia? You may want to explore these links:

Review: Microglia in motor neuron disease

Motor cortex transcriptome reveals microglial key events in amyotrophic lateral sclerosis

Which drug reduces the autoimmune risks of alemtuzumab?

Mitigating alemtuzumab-associated autoimmunity in MS: a “whack-a-mole” B-cell depletion strategy Meltzer E, Campbell S, Ehrenfeld B, et al. Neurol Neuroimmunol Neuroinflamm 2020; 7:e868. Abstract Objective To determine whether the punctuated administration of low-dose rituximab, temporally linked to B-cell hyperrepopulation (defined when the return of CD19+ B cells approximates 40%-50% of baseline levels as measured before alemtuzumab […]

Which drug reduces the autoimmune risks of alemtuzumab? — Neurochecklists Blog

What are the 695 topics that make up neurology?

The goal of Neurochecklists is to bring everything even remotely neurological under one roof. It set out to be a practical, comprehensive, easily searchable, on-the-go database. Sourcing information from reliable textbooks and journals, the database has slowly grown to peak today at >3,000 checklists spread across precisely 695 topics. These topics, in turn, are grouped […]

What are the 695 topics that make up neurology? — Neurochecklists Blog

The remarkable scope of neurology…in 83 revealing numbers

Exploring Neurochecklists is a revealing experience… It always highlights the expansive range of neurological disorders. To illustrate this extensive breadth and scope of neurology… Here are 83 striking numbers..all linked to their checklists. 83. Numbers in a city: New Haven, CT. See Ming-Lee on Flickr https://www.flickr.com/photos/seeminglee/142117353 11 neurological complications of aortic dissection 11 causes of […]

The remarkable scope of neurology…in 83 revealing numbers — Neurochecklists Blog

Which anti-MOG antibody treatment has the lowest relapse risk?

Steroid-sparing maintenance immunotherapy for MOG-IgG associated disorder. Chen JJ, Flanagan EP, Bhatti MT, et al. Neurology 2020; 95:e111-e120. Abstract Objective Myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG) associated disorder (MOGAD) often manifests with recurrent CNS demyelinating attacks. The optimal treatment for reducing relapses is unknown. To help determine the efficacy of long-term immunotherapy in preventing relapse in […]

Which anti-MOG antibody treatment has the lowest relapse risk? — Neurochecklists Blog

Is thrombolysis beneficial for central retinal artery occlusion?

Intravenous fibrinolysis for central retinal artery occlusion: a cohort study and updated patient-level meta-analysis. Mac Grory B, Nackenoff A, Poli S, et al. Stroke 2020; 51:2018-2025. Abstract Background  Central retinal artery occlusion results in sudden, painless, usually permanent loss of vision in the affected eye. There is no proven, effective treatment to salvage visual acuity […]

Is thrombolysis beneficial for central retinal artery occlusion? — Neurochecklists Blog

The 7 most hazardous occupations to the nervous system

A critical part of history taking in medicine is establishing the occupation of the patient. This is because occupational activities and work place exposures are often major contributors to the disease. Furthermore, at the end of the medical process, the eventual diagnosis may have an impact on the patient’s ability to return to work. To be relevant, the occupational history must be exhaustive – it must establish current and past occupations, the tasks carried out, the risk of toxic exposure, and the use of personal protective equipment (PPE). The occupational history is so important to neurology that a whole subspecialty, occupational neuroscience, has emerged to evaluate “the effects of complex environmental and occupational exposure on working people”.

By Ford Madox Brown1QG5Dp3Ti29BxA at Google Cultural Institute, zoom level maximum, Public Domain, Link

So what are the occupational hazards that may lead a patient to the neurologist? Below are my 7 most hazardous occupations to the nervous system

Working together for the commune. Jrwooley6 on Flickr. https://www.flickr.com/photos/jordan_wooley/3861487721

Typing

Previously an occupational hazard restricted to professional typists, carpal tunnel syndrome (CTS) now threatens anyone who uses a computer. CTS develops when the median nerve is entrapped at the wrist, and it manifests as weakness and sensory disturbances over the thumb, the index finger, the middle finger, and half of the ring finger. Whilst desk work is the main risk of CTS, manual workers are not spared the peril because the occupations that increase the risk of CTS include assembly work, food processing and packing, and the use of hand-help powered vibratory tools. And, by the way, vibrating tools also predispose to cubital tunnel syndrome, entrapment of the ulnar nerve at the elbow which presents as weakness and sensory impairment of the little finger, and half of the ring finger (you now know why it was chosen for the wedding ring). Cubital tunnel syndrome, again by the way, also happens to be an occupational hazard of truck drivers, baseball pitchers, and golfers. Just saying.   

Tele typist (ghostwriter). Matthew Hurst on Flickr. https://www.flickr.com/photos/skewgee/4858837387

Farming 

Farming is actually a relatively innocent bystander with this occupational risk, the neurological hazard arising from exposure to pesticides. And the neurological consequence of pesticide use is Parkinson’s disease (PD), a threat that is established without any equivocation. All pesticides carry the same degree of PD risk, but the badge of ignominy surely belongs to organophosphates and carbamates. The risk of PD is however not all-or-none because it is proportional to the duration of exposure. And, as if PD wasn’t enough, pesticides also seem to increase the risk of developing Alzheimer’s disease (AD). I’m just the messenger!

By Manly MacDonaldhttps://www.warmuseum.ca/collections/artifact/1016823, Public Domain, Link

Welding

An almost iconic neurological occupational risk-relationship is the association of welding and Parkinson’s disease (PD). Along with the related tasks of galvanizing and grinding, welding releases fumes of manganese (Mn), the metal that is suspected to be the PD-trigger in this case. As with pesticides, the risk appears to be proportional to the degree of exposure. But unlike pesticides, the reported PD risk of manganese is equivocal because some studies have not found any relationship between welding fumes and PD; indeed one found an inverse relationship between the two, reporting that welding reduces the risk of PD. Surely there are no fumes without fire, but in spite of this minor controversy, or because of it, neurologists are forever vigilant for manganese fumes when they make a diagnosis of PD; they are aware, after all, that only more data will clear the fumes. As an addendum, many other occupations, from teaching to computer programming, reportedly increase the risk of developing PD – presumably because of occupational stress!

By DoriOwn work, CC BY-SA 3.0 us, Link

Smelting

Just as welding conferred notoriety on manganese, so has smelting endowed lead (Pb) with infamy. And the metal’s neurological ignominy is the peripheral neuropathy it evokes. The classical but rarer form of lead neuropathy, is a subacute motor neuropathy which is a manifestation of lead-induced porphyria. Far more common is a chronic sensory neuropathy which is considered to be the direct result of lead toxicity. Beyond neuropathy, chronic lead exposure has garnered disrepute for its reported links with motor neurone disease (MND), although this risk association is contested. In fairness to Pb, other periodic table elements such as thallium (Tl) and arsenic (As) also pose significant occupational risks of neuropathy. And whilst still on metals, it is worth pointing out the report that occupational exposure to iron (Fe) may be a risk factor for meningiomas. Dmitri Mendeleev must be turning in his grave!

By Alfred T. Palmer – This image is available from the United States Library of Congress‘s Prints and Photographs divisionunder the digital ID fsac.1a35280.This tag does not indicate the copyright status of the attached work. A normal copyright tag is still required. See Commons:Licensing for more information., Public Domain, Link

Music

Neurologists, particularly of the movement disorder fraternity, listen to the occupational history of their patients with very keen ears, which literally prick up when they hear that the patient is a musician. This is because a large swathe of musical instruments predispose musicians to career-threatening task-specific dystonia, a form of dystonia which targets muscles that are most frequently exerted, especially in performing delicate actions. Whilst this umbrella diagnosis embraces such non-musical disorders as writer’s cramp, runner’s dystonia, and croupier’s cramp, it is musician’s dystonia that constitutes the widest spectrum of task-specific dystonia. And the reason is not far-fetched: playing musical instruments professionally requires the repetitive performance of very exquisite motor skills over long periods of time. Initially, the dystonia is only evident whilst playing the musical instrument, but it eventually manifests during unrelated tasks, and even at rest. The diversity of symptoms of musician’s dystonia is rivalled only by the number of instruments in the music ensemble, ranging from finger incoordination to upper lip tremor. Singers are also at risk of dysphonia, a form of voice dystonia which they share with teachers, telemarketers and aerobic instructors – all potential victims of hoarseness and voice fatigue.

Musical instrument sculpture in MAMAC in Nice, France. Karen Bryan on Flickr. https://www.flickr.com/photos/europealacarte/17700661556/

Sports

Unsurprisingly, competitive sports takes a heavy toll on the nervous system. At the fairly benign end of the spectrum is the compression of nerves, the innocent victims of grotesquely enlarged, almost mythically Herculean, muscles. Many nerves may be stretched or trapped by a long list of risky sports which includes archery, ballet, baseball, basketball, bowling, football, golf, hockey, tennis, weightlifting, gymnastics, and wrestling. And the classic sport-related nerve entrapment is that of the long thoracic nerve which manifests as scapular winging. Unfortunately, many sporting-related neurological hazards lie at the malign end of the spectrum, with such appalling diseases as chronic traumatic encephalopathy (CTE) from repetitive contact sports; Parkinson’s disease from the boxing related head injuries; and motor neurone disease (MND) especially from professional football. As with most such risks, the evidence for some sports-related neurological hazards is often anecdotal, but very difficult to dismiss in a neurology clinic.

Leicestershire. Ann and David on Flickr. https://www.flickr.com/photos/annedavid2012/42872566454

Shift work

This is, of course, a no brainer as every shift worker knows. Sleep disruption is the most prominent, but by far not the most serious hazard of burning the midnight candle at work. It is common knowledge that shift work reduces alertness, thereby compromising work performance. But more seriously, shift work increases the risk of several neurological disorders such as stroke, epilepsy, Parkinson’s disease (PD), Alzheimer’s disease (AD), and even multiple sclerosis (MS). As if these are not enough, shift work also predisposes to malignancies such as breast cancer and colon cancer, apart from impairing the function of many organs. Indeed the number of disorders now grouped under the remit of shift work sleep disorder (SWSD) is mind-numbing (apologies, I can’t conjure up a better pun). The reason shift work is such a medical nuisance is that it disrupts the brain’s critical circadian rhythm, thereby impairing the production of melatonin, a hormone that plays a hugely critical neuroprotective role. So think twice before taking that next lucrative night shift!

Insomnia. Joana Coccarelli on Flickr. https://www.flickr.com/photos/narghee-la/7294549116

***

I suppose the key message of this blog post is…choose your profession wisely!

A few more helpful and practical neurology checklists

In our continuing zeal to maintain a grip on all of neurology, We regularly add to our already exhaustive database of checklists. As a taster of what we have recently done, Below are 15 brand new checklists expanding our horizon. *** Acute amnestic syndromes   Alzheimer’s disease preventative measures  Antiplatelet resistance: causes Antiplatelet resistance: management  Encephalocraniocutaneous […]

A few more helpful and practical neurology checklists — Neurochecklists Blog

Monumental breakthroughs in the history of neuroscience

It is difficult to really say when neuroscience began, but most sources trace the first account of the nervous system to what is now known as the Edwin Smith papyrus; this is an Egyptian text written around 1700 B.C which documents surgical procedures for brain trauma. Since then, neuroscience breakthroughs have come at breakneck speed. The sources I have consulted for this blog post, referenced at the end, name innumerable discoveries made by countless innovators. To attempt to put a number to the most important breakthroughs will therefore be a well-nigh impossible task. So I came up with the idea of chunking key discoveries under distinct sections or systems of the nervous system.

By Jeff Dahl – Edited version of Image:EdSmPaPlateVIandVIIPrintsx.jpg, Public Domain, Link

But even this plan to chunk key breakthroughs came with strong challenges. For example, it is not always clear when a discovery was first made, or who crossed the finishing line first. This is because there are often several contenders in a tight race to the finish, and only a few discoveries were definite one-man paradigm-changing works. On the contrary, most discoveries were made by two or three pioneers working in a creative partnership, or by larger groups of people working in innovative collaborations. A further challenge was establishing what or where the finishing line was, as this is not always well-defined; this is understandable because most scientific advances were made over centuries, in small incremental steps, in a gradual progression from basic observation to complex synthesis.

Achievement. Gregory Vozzo on Flickr. https://www.flickr.com/photos/revgv/32592150306

To overcome these challenges, I have avoided too much emphasis on the ‘who first‘ conundrum that drives, and sometimes mires, science. I have also side-stepped the ‘when first‘ problem by noting only a few dates just to maintain some sense of chronology. I did a lot of picking and choosing for this post, and it is inevitable that somebody’s favourite discovery, or discoverer, would be missing; take heart and exult in the collective effort that has gone into these monumental breakthroughs in the history of neuroscience.

***

Cerebrospinal fluid (CSF)

It is difficult to pinpoint who first described the cerebrospinal fluid (CSF) circulation but Nicolo Massa, Lewis Weed, Gustav Retzius, Francois Magendie and Albrecht von Haller have all been cited. The names associated with accurately describing the constituents of CSF are William Halliburton and William Mestrezat. Franciscus de la Boe Sylvius is credited with describing the aqueduct of Sylvius, and Alexander Monro for describing the foramen of Monro. Antonio Pacchioni discovered arachnoid granulations, whilst Guilio Cesare and Thomas Willis are credited for describing the anatomy and function of the choroid plexus. The accurate description of the blood brain barrier has been attributed to both Max Lewandowsky and Paul Erlich.

By © Nevit Dilmen, CC BY-SA 3.0, Link

Brain mapping

Cerebral localisation of functions has always been, and continues to be, a key neuroscience task. As brain functions become increasingly recognised as network-based, rather than region-based, cerebral localisation is taking more of a back seat in neuroscience. But it is still worthwhile to acknowledge the pioneers who identified key brain areas. Paul Broca is credited with the first description of the cortical speech area, whilst motor function localisation is traced to the works of Eduard HitzigGustav Fritsch, David Ferrier, and Victor Horsley. The classification of cerebral areas into 52 parts was done by Korbinian Brodmann, whilst it was neurosurgeon Wilder Penfield who defined the cortical maps of the motor and sensory homunculus.

By BkroegerOwn work, CC BY-SA 3.0, Link

Central nerves

Both Rudolph Virchow and Heinrich Müller are credited with describing neuroglia. The credit for classifying these into microglia and oligodendroglia goes to Pio del Rio Hortega, whilst that for describing dendrites and axons goes to Otto Friedrich Karl Deiters. Camillo Golgi introduced the critical silver nitrate method of staining nerve cells, a technique advanced by Santiago Ramon y Cajal, who developed the gold chloride-mercury method for staining astrocytes. The description of the synapse is attributed to the truly great Charles Scott Sherrington. W. Bevan Lewis, Vladimir Betz and Johannes Purkinje have all been credited with describing the giant motor nerves of the cortex.

PSA+NCAM+neuron. Jason Snyder on Flickr. https://www.flickr.com/photos/functionalneurogenesis/4573320569

Cranial nerves

Rufus of Ephesus is named as the first person to describe and name the optic chiasma. Other cranial nerve achievements are the discovery of the tenth cranial nerve by Marinus, and the description of seven cranial nerves by Rhazes. The trochlear and abducens nerves were described by Gabriele Falloppio, and it was Samuel Thomas von Soemmerring who introduced the current classification of the twelve cranial nerves.

By OpenStax – https://cnx.org/contents/FPtK1zmh@8.25:fEI3C8Ot@10/Preface, CC BY 4.0, Link

Peripheral nerves

The credit for distinguishing between myelinated and unmyelinated nerves goes to Robert Remak, whilst the credit for describing myelin formation goes to Theordor Schwann. It was Louis-Antoine Ranvier who described the gaps between myelin sheaths called the nodes of Ranvier. The different types of sensory nerves were described by Herbert Gasser, and it was Friedreich Merkel who described the sensory receptors now known as Merkel corpuscles. Credit for describing the cutaneous distribution of sensory nerves goes to Henry Head, and it was Francois Magendie who recognised the different functions subserved by the dorsal and ventral nerve roots of the spinal cord.

By BruceBlausOwn work, CC BY 3.0, Link

Nerve conduction

The early understanding of how nerves function has a lot to do with the description by Hermann Helmholtz of the electrical nerve impulse velocity. The resting membrane potential was described by Julius Bernstein and Walter Nernst, whilst Keith Lucas and Edgar Adrian measured peripheral nerve impulses, Adrian going on to confirm that nerve impulses are all or none. Alan Hodgkin and Andrew Huxley are credited with describing the mechanisms of action potentials, whilst Joseph Erlanger and Herbert Spencer Gasser described the function of single nerve fibers.

By JanbroggerOwn work, Public Domain, Link

Chemical neurotransmission 

Whilst nerve function is electrical, it is chemicals that bridge the gap between nerves. The chemical neurotransmitters of peripheral nerves, norepinephrine and acetylcholine, were isolated by George Barger and Henry Dale. The credit for establishing chemical neurotransmission between nerves and muscles, at the neuromuscular junction, goes to Otto Loewi‘s dream-inspired work on Vagusstoff. The discovery of the central nervous system neurotransmitter GABA is credited to Eugene Roberts and Jorge Awapara. Most of the later work on neurotransmitters were made by Julius Axelrod, Bernard Katz and Ulf Svante von Euler, and the credit for elucidating the function of ion channels goes to Erwin Neher and Bert Sakmann.

By Doctor Jana – https://docjana.com/neuro-muscular-junction/, CC BY 4.0, Link

Special senses

The visual system is fundamental to neuroscience, and credit for describing its mechanism goes to Ragnar Granit, Halden Hartline and George Wald. The merit for elucidating the details of visual processing goes to David Hubel and Torsten Wiesel. The sense of smell is similarly important, and initial work on this was made by David Ferrier, but it is to Linda Buck and Richard Axel that kudos go for discovering odour receptors, and for describing the configuration of the olfactory system.

 

By Wiley – Wikimedia, CC BY-SA 3.0, Link

Memory, pain, and prions

The acclaim for establishing the anatomical foundations of memory goes to Brenda Milner for her work on Patient HM. It is however Eric Kandel who has the honour of working out the functional process of memory formation. The gate control theory of pain was established by Ronald Melzack and Patrick Wall, whilst credits for establishing the nature of prion diseases go to the lively Daniel Carleton Gajdusek, and the indefatigable Stanley Prussiner.

Prion Proteins and Mouse Nerve Cells. NIH Image Gallery on Flickr. https://www.flickr.com/photos/nihgov/48440889002

Navigation, mirror neurones, and growth factors

The brain’s positioning system was discovered by John O’Keefe, Edvard Moser, and May-Britt Moser. Cedit for discovering mirror neurones goes to Giacomo Rizzolatti, whilst Rita Levi-Montalcini and Stanley Cohen were the first to isolate nerve growth factor.

 

Compass rose. Margaret W. Carruthers on Flickr. https://www.flickr.com/photos/64167416@N03/7022634029

 Brain circulation and brain waves

Thomas Willis, Henry Duret and Johann Heubner first described the arterial circulation of the brain, whilst the electrical brain wave activity of the brain was first recorded by Hans Berger, incidentally when he was investigating telepathy.

By OpenStax College – Anatomy & Physiology, Connexions Web site. http://cnx.org/content/col11496/1.6/, Jun 19, 2013., CC BY 3.0, Link

***

And so ends this rapid whizz through the annals of neuroscience. This is just the condensed tip of the iceberg; to learn more about the fascinating giants who defined the glorious history of neuroscience, you may wish to slowly digest the following sources:

Websites

Milestones in Neuroscience Research

A Short History of European Neuroscience

Books

Minds Behind the Brain

Dates in Neurology