Few fields of medicine have transformed human life as profoundly as neurology. The story of how we came to understand the brain and nervous system is not a straight line – it is a series of surprising experiments, fierce intellectual debates, and hard-won clinical breakthroughs spanning centuries. From the first inklings that electricity powers the body’s signaling network to the invention of tools that can eavesdrop on brain waves in real time, each milestone has pushed the boundary of what is treatable and what is knowable about the human mind.

Early foundations: studying nerve function
Mapping the brain: the neuron doctrine and localization
The invention of the EEG: listening to the brain
Drug therapies: from trial and error to targeted treatment
Epilepsy treatments
Parkinson’s disease and levodopa
Psychiatric and broader neurological drugs
From anatomy to technology: the broader arc of neurological progress

Early foundations: studying nerve function

For most of human history, the nervous system was explained through the concept of “animal spirits” – invisible fluids believed to flow through hollow nerves and animate the body. This idea, originating with the ancient physician Galen and reinforced for over a millennium, began to crumble in the 18th century when scientists started applying the newly understood phenomenon of electricity to living tissue.

The pivotal figure in this shift was Luigi Galvani, a professor of anatomy at the University of Bologna. In the 1770s, Galvani began conducting experiments with frogs, observing that their leg muscles contracted when touched by a metal scalpel near an electrical machine. After nearly a decade of meticulous work, he published his findings in 1791 in a landmark treatise, arguing that animals possess an intrinsic electricity that the nervous system uses to send messages throughout the body. He also proposed that nerves must be sheathed in a fatty, insulating material – a hypothesis that would be confirmed more than sixty years later with the discovery of myelin. While not every detail of Galvani’s theory proved correct, his core insight was revolutionary: the animal spirits doctrine began to fall out of favour, replaced by a model of nerve function that could be observed and measured.

Shortly after, German physiologist Hermann von Helmholtz built on this foundation by demonstrating that electrical impulses in nerves were not mere by-products but meaningful carriers of information. He measured that these impulses travel at approximately three metres per second – surprisingly slow compared to electrical conduction in a copper wire – confirming that nerve signalling was a biological, not purely physical, process.

Mapping the brain: the neuron doctrine and localization

Even as the electrical nature of nerve function was being established, scientists were still deeply divided on how the nervous system was actually organized. The dominant view through much of the 19th century was the reticular theory – the idea that the entire nervous system formed one continuous, fused web of fibers. It took a remarkable collaboration and rivalry to overturn it.

In 1873, Italian scientist Camillo Golgi developed the “black reaction,” a silver nitrate staining technique that, for the first time, revealed the full silhouette of individual nerve cells under a microscope. Golgi used his own observations to argue for the reticular theory, believing the stained cells formed one unified mass. But a Spanish physician, Santiago Ramón y Cajal, adapted Golgi’s staining method and reached the opposite conclusion.

In 1888, Cajal posited that the nervous system was not a continuous network but instead composed of discrete individual cells that communicate through close contact – what would later be termed synapses. His neuron doctrine established that nerve cells are the structural and functional units of the nervous system, transmitting impulses in one direction. This was not just a structural observation; it provided the physical basis for understanding how learning, memory, and neurological disorders actually work. In 1906, both Golgi and Cajal were awarded the Nobel Prize in Physiology or Medicine – though, ironically, the two men remained fiercely opposed in their interpretations to the very end.

Around the same time, clinicians were making equally important strides in mapping what different brain regions do. French surgeon Paul Broca, in 1861, autopsied a patient who had lost the ability to speak and traced the deficit to a specific lesion in the left frontal lobe – now known as Broca’s area, the brain’s speech command centre. Carl Wernicke soon identified a separate region responsible for language comprehension. John Hughlings Jackson demonstrated that seizures followed organized electrical patterns across the motor cortex. Jean-Martin Charcot, whom Britannica identifies as the “founder of modern neurology,” spent decades at the Salpêtrière Hospital in Paris distinguishing organic neurological disease from psychiatric conditions – a separation that allowed neurology to emerge as a rigorous, independent discipline.

The invention of the EEG: listening to the brain

The 20th century opened a new chapter in neurology with the first technology capable of recording the brain’s own electrical activity without surgery. That technology was the electroencephalogram, and its creator was Hans Berger, a German psychiatrist whose path to the invention was deeply personal.

Berger had long been fascinated by the possibility of thought transmission between people – a near-miss with death in his youth left him convinced he had telepathically communicated his fear to his sister. His quest for a scientific basis for that experience led him, indirectly, to study the brain’s electrical output. On July 6, 1924, at the University Hospital in Jena, Berger successfully recorded the first human brain electrical signal, using electrodes placed on the scalp of a seventeen-year-old surgical patient. He spent five more years verifying and refining the technique before publishing his findings in 1929 under the title “Über das Elektrenkephalogramm des Menschen” (On the Electroencephalogram of Man). He was the first to describe distinct brain wave patterns, naming them alpha and beta waves – with the slower alpha rhythm, now also called “Berger’s wave,” appearing when the subject was relaxed with eyes closed.

His reception was initially cold. The scientific community was skeptical that a psychiatrist had made such a foundational discovery in neurophysiology. Berger’s findings went largely unnoticed until Nobel laureate Edgar Adrian confirmed the results and began publicizing both the method and its inventor. By 1938, the EEG had gained widespread adoption in the United States, England, and France as a diagnostic tool.

The impact on clinical practice was immediate. The EEG, combined with lumbar puncture analysis and cerebral angiography, gave neurologists far greater precision in diagnosis and opened the door to targeted therapies. It revolutionized daily neurological and neurosurgical procedures and served as the primary non-invasive diagnostic bridge for roughly forty years – from 1930 until the advent of computed tomography in the 1970s. Today, the EEG remains an essential tool for diagnosing epilepsy, sleep disorders, brain injuries, and monitoring states of consciousness.

Drug therapies: from trial and error to targeted treatment

For most of neurology’s early history, the field was – as one review in European Neurology describes it – “a purely observational discipline, focused on pathology and with little interest in treatments.” That changed decisively over the 20th century, driven by a combination of careful pharmacological research and a significant amount of serendipity.

Epilepsy treatments

Epilepsy was among the first neurological conditions to yield to pharmacological intervention. Phenobarbital became available as an anticonvulsant in 1904, and diphenylhydantoin (phenytoin) followed in 1938, after Merritt and Putnam demonstrated its specific anticonvulsant action. These drugs transformed epilepsy from a highly stigmatized and largely unmanageable condition into one that millions of people could live with. The development of later anticonvulsants – including carbamazepine and valproate – further refined treatment options, and EEG-guided surgical interventions such as temporal lobectomy added another powerful tool for patients whose seizures did not respond to medication.

Parkinson’s disease and levodopa

One of the most celebrated examples of neuropharmacology’s power is the story of levodopa (L-DOPA) in Parkinson’s disease. Parkinson’s was understood by the mid-20th century to involve a loss of dopamine-producing neurons in the substantia nigra. The history of L-Dopa in neurology illustrates the major shift toward neuropharmacology as a research paradigm after mid-century. Levodopa, a precursor that the brain can convert into dopamine, dramatically reduced the motor symptoms of Parkinson’s in many patients – transforming lives and demonstrating that a detailed chemical understanding of brain disease could lead directly to effective therapy.

Psychiatric and broader neurological drugs

Many molecules were tested through trial and error, often based on similarities between diseases, and chance played a significant role. The discovery of chlorpromazine in the early 1950s as an antipsychotic – initially investigated as a surgical anesthetic enhancer – opened an entirely new era in treating schizophrenia and other severe psychiatric disorders. Antidepressants followed, reshaping the treatment of mood disorders. The introduction of intravenous immunoglobulins and later monoclonal antibodies (such as natalizumab and rituximab) transformed the management of immune-mediated conditions like multiple sclerosis. More recently, oligonucleotide therapies have been deployed in spinal muscular atrophy, a previously untreatable genetic disorder in infants, representing one of the most targeted interventions in neurological medicine to date.

From anatomy to technology: the broader arc of neurological progress

What emerges from this history is a clear pattern: each major tool or concept – whether Galvani’s electrical model of nerves, Cajal’s neuron doctrine, Berger’s EEG, or the pharmacological revolution – gave rise to entirely new ways of diagnosing and treating neurological disease. Advances in neuroimaging, electroencephalography, electromyography, biochemistry, and neuropharmacology have considerably improved the ability to evaluate and treat patients with neurological disorders, from epilepsy and Parkinson’s to multiple sclerosis and rare genetic conditions.

The 21st century has added further dimensions. The Human Genome Project, completed in 2001, fuelled the identification of single gene defects contributing to neurological disorders, while brain-computer interfaces are now enabling paralysed patients to control devices through thought alone. Neuroimaging has moved from static anatomical maps to dynamic functional portraits of the brain at work. Artificial intelligence is being applied to predict disease progression and personalize treatment plans. The field has also expanded into subspecialties – neuro-oncology, neuromuscular medicine, pediatric neurology, and neurocritical care – each with its own diagnostic tools and therapeutic strategies.

Yet the history of neurological treatment has not been one of constant progress. Remarkable success in some areas – epilepsy, multiple sclerosis, and Parkinson’s disease – stands alongside near-stagnation in others, including many brain tumours and amyotrophic lateral sclerosis (ALS). Some of these intractable conditions trace their mysteries back to foundational questions that Charcot himself was already posing in the 19th century. The unknowns that remain are a reminder that the history of neurology is still being written.

What do you think? Given that so many neurological breakthroughs – from Galvani’s frog experiments to Berger’s EEG – emerged partly from unexpected angles, what does that suggest about how we should structure scientific research today? And as drug therapies grow more targeted and personalized, do you think a pharmacological understanding of the brain will ever be sufficient on its own to explain consciousness?

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Milestones in Neurological Research: A Historical Overview

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Milestones in Neurological Research: A Historical Overview

Table of Contents

Early foundations: studying nerve function 🔗

Mapping the brain: the neuron doctrine and localization 🔗

The invention of the EEG: listening to the brain 🔗

Drug therapies: from trial and error to targeted treatment 🔗

Epilepsy treatments 🔗

Parkinson’s disease and levodopa 🔗

Psychiatric and broader neurological drugs 🔗

From anatomy to technology: the broader arc of neurological progress 🔗