For most of human history, the brain was a quiet monarch. It ruled thoughts, emotions, decisions, and the delicate balance of sanity, yet it kept its workings concealed behind bone and mystery. Physicians could watch the body fail, tremble, convulse, or fall unconscious, but they could never listen to the brain itself.
It was a world of symptoms without soundtracks.

The turning point came not through a grand laboratory or a global team of scientists, but through the quiet persistence of a single man.

The Psychiatrist Who Discovered the Brain’s Music

In 1924, a modest German psychiatrist named Hans Berger began wiring electrodes to the scalp in an attempt to record electrical activity. His colleagues considered the idea eccentric — “the brain is too well-shielded,” they said. But Berger had an intuition: somewhere beneath the skull, the brain produced rhythms, and if one listened patiently enough, those rhythms might reveal themselves.

His equipment was crude. His amplifiers were weak. His recordings required long, delicate exposures on photographic paper. Yet he persisted with the devotion of a man convinced he was uncovering a deeper truth.

And then he saw it.
A gentle, rhythmic oscillation at about ten cycles per second — the first human brainwave ever captured, later named the alpha rhythm.

Berger had not just discovered a wave.
He had discovered a language.

Human brain rhythms were no longer myth. They were measurable, recordable, and interpretable. The brain was speaking, and at last, someone had heard.

Why EEG Still Feels Like Magic

Nearly a century later, in an era filled with MRIs, CT scans, and complex neuroimaging software, EEG remains uniquely powerful — a tool that captures not structure, but function.
Not anatomy, but the unfolding moment-to-moment life of the brain.

EEG is the heartbeat of the cortex.
It shows the brain thinking, resting, drifting, falling asleep, seizing, recovering, or deteriorating — not at the pace of minutes, but milliseconds.

It is a living conversation with the nervous system.

What EEG Really Measures

The classic teaching file, How to Interpret an EEG and Its Report , describes EEG as a scalp recording of brain-wave activity .
But this simple definition hides something far more elegant.

EEG does not record action potentials — those fierce spikes that neurons fire.
It records the summated postsynaptic potentials (EPSPs and IPSPs) of cortical pyramidal cells — slow, graceful electrical shifts created when thousands of neurons activate together.

These neurons are arranged like a forest of tall trees. When they tilt in harmony, their collective electrical field passes upward through cerebrospinal fluid, skull, and scalp.

Electrodes detect this as waves.
Every smooth curve, every burst, every spike on the graph is a reflection of millions of neurons moving in synchrony.

This is why an EEG feels less like reading a test and more like listening to an orchestra.

The Poetry of Brain Rhythms

The brain doesn’t produce random static. It generates structured rhythms — each with its own frequency, personality, and clinical meaning. These rhythms, illustrated beautifully across pages 21–27 of the handbook, form the foundation of EEG interpretation [1].

Delta (1–3 Hz): The Deep Earthquake

Slow, high-amplitude waves.
Present during deep sleep, diffuse encephalopathy, or structural lesions.

Theta (4–7 Hz): The Borderlands

The drifting rhythm of drowsiness.
Normal in children, suggestive of dysfunction when diffuse in adults.

Alpha (8–13 Hz): Berger’s First Whisper

The tranquil hum of an awake, relaxed mind.
Posterior-dominant when eyes are closed — the signature of a neurologically stable cortex.

Beta (>13 Hz): The Quickened Mind

Fast, low-amplitude waves.
Enhanced by benzodiazepines, anxiety, and attention.

Together, these rhythms form the canvas upon which every abnormality will later stand out.

The Beauty of a Normal EEG

A normal EEG — the serene example on page 27 — is a portrait of harmony [1].
It shows:

• a symmetric alpha background,

• smooth transitions,

• no erratic spikes or sharp waves,

• appropriate reactivity to photic or hyperventilation stimuli.

A normal EEG is like a calm ocean.
Every pathology is a ripple, a storm, or a sudden tide breaking this calm.

Why EEG Matters More Than Ever

Despite advances in neuroimaging, EEG remains indispensable for one reason: it captures time.

It reveals:

• the onset of a seizure,

• the fading pulse of a recovering cortex,

• the slowing of encephalopathy,

• the architecture of sleep,

• the asymmetry of a focal lesion,

• the hyperexcitability of epileptiform states.

EEG allows us to hear the brain speak in the present moment — something no scan can do.

What Comes Next in This Series

In the next article, we move from the poetic to the practical — learning about montages.
Bipolar, referential, transverse, longitudinal, Z-montages — each of them acts like a different lens, altering what you see and what you miss.

Once you understand montages, EEG ceases to be intimidating squiggles and becomes a structured, decipherable language.

About the Author

Dr. Srinivas Rajkumar T, MD (AIIMS), DNB, MBA (BITS Pilani)
Consultant Psychiatrist & Neurofeedback Specialist
Mind & Memory Clinic, Apollo Clinic Velachery (Opp. Phoenix Mall)
✉ srinivasaiims@gmail.com 📞 +91-8595155808