EEG Basics: A Beginner's Guide to Electroencephalography
Electroencephalography (EEG) is one of the most accessible ways to observe brain activity in real time. This guide covers everything you need to know to get started.
What Is EEG?
Electroencephalography (EEG) is a non-invasive method that records electrical activity produced by neurons in the brain. Small sensors placed on the scalp detect voltage fluctuations caused by ionic currents flowing through large populations of neurons.
Since its discovery by Hans Berger in 1924, EEG has become a cornerstone of neuroscience research, clinical diagnosis, and — more recently — consumer neurotechnology products.
How EEG Works
EEG electrodes detect the summed post-synaptic potentials of thousands of neurons firing in synchrony. The signal is amplified, digitised, and displayed as a continuous waveform measured in microvolts (µV).
Key Concepts
- Electrode placement — The international 10-20 system standardises where sensors sit on the scalp.
- Sampling rate — Consumer devices typically sample at 250 Hz; clinical systems at 500–2000 Hz.
- Artifacts — Eye blinks, muscle movement, and electrical noise must be filtered out during analysis.
Brainwave Frequency Bands
EEG signals are decomposed into frequency bands, each associated with different mental states:
| Band | Frequency | Associated State |
|---|---|---|
| Delta (δ) | 0.5–4 Hz | Deep sleep |
| Theta (θ) | 4–8 Hz | Drowsiness, meditation |
| Alpha (α) | 8–13 Hz | Relaxed wakefulness |
| Beta (β) | 13–30 Hz | Active thinking, focus |
| Gamma (γ) | 30–100 Hz | Higher cognitive processing |
Consumer EEG Devices
A new generation of affordable EEG headsets has made brain monitoring accessible outside the lab. Devices like the Neurosity Crown, Muse, and OpenBCI allow researchers, developers, and enthusiasts to record EEG data at home.
What to Look For
- Channel count — More channels provide better spatial resolution.
- Sampling rate — Higher rates capture faster brain dynamics.
- Comfort & form factor — Wearability matters for longer recording sessions.
- Data access — Open APIs enable custom analysis and integration with tools like NeuroFusion.
Applications of EEG
- Clinical diagnosis — Epilepsy detection, sleep disorder evaluation, and brain injury assessment.
- Cognitive research — Studying attention, memory, and decision-making processes.
- Brain-computer interfaces — Translating brain signals into device commands.
- Wellness & self-quantification — Tracking focus, relaxation, and meditation quality.
Getting Started with EEG
NeuroFusion makes it easy to start recording and analysing your EEG data. Connect a supported device, run a quest, and explore your brainwave patterns.