How do brain scans work?

Our brains are protected by the skull which makes it challenging to study it. That’s why brain scans are used.

Brain scans are used to produce detailed images of the brain. They can be used to detect and diagnose conditions such as tumors or other neurological diseases.

Various techniques are used for scanning the brain. Each technique measures something different. Those techniques are as follows:

  • Electroencephalography (EEG)
  • Functional Magnetic Resonance Imaging (fMRI)
  • Positron Emission Tomography (PET)



EEG measures electrical activity in our brain. When brain cells communicate they produce waves of electricity, EEG can help to detect if problems are associated with this activity in just milliseconds.
Electrodes are placed on the skull that picks up the waves of electricity produced by brain cells; the differences in the signals detected between electrodes provide information about brain’s activity.
EEG is used to diagnose conditions like epilepsy and sleep disorders. It also helps to investigate what areas of the brain are active during learning.

Functional Magnetic Resonance Imaging

EEG can detect when certain activity occurs, fMRI is the technique that can detect where it occurs. It measures brain activity by detecting changes in the blood flow. It measures how quickly oxygen gets consumed by the brain cells. When a person performs a behavioral task we can observe which part of the brain is active as more oxygen is used in the active area. This helps us to study how we understand our emotions and surroundings.

Positron Emission Tomography

In this technique, a small amount of radioactive material (tracer) is injected into bloodstream. Doctors monitor its circulation through the brain. It is useful to study how drugs affect the brain and detecting neurological diseases.


While these scans help us to understand our brain, there still exists a limitation because of how much we don’t know. Until then our brains will keep working to find a way to explore new ways of understanding itself.

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