EEG stands for Electroencephalography. It's a neurophysiological test that measures and records the electrical activity of the brain. Here's a more detailed explanation:

Key Concepts:

  • Electrical Activity: The brain's neurons communicate with each other through electrical signals. These signals are tiny voltage fluctuations that change rapidly.
  • Electrodes: EEG uses small, metal discs called electrodes that are attached to the scalp using a conductive paste or gel. These electrodes are essentially sensors that pick up the electrical signals coming from the brain.
  • Amplification: The electrical signals detected by the electrodes are very weak, so they need to be amplified by special equipment. This amplified signal is then recorded.
  • Wave Patterns: The EEG recording is presented as a series of wavy lines, often referred to as brainwaves. These waves vary in their frequency (speed) and amplitude (height), and different wave patterns are associated with different states of brain activity.
  • Non-Invasive: EEG is a non-invasive procedure, meaning it doesn't involve any surgery or injections.

What EEG Does:

  • Measures Brain Activity: EEG primarily measures the electrical activity arising from the cerebral cortex, the outer layer of the brain responsible for many higher cognitive functions.
  • Detects Brain Disorders: It's used to help diagnose and monitor various neurological conditions such as epilepsy, sleep disorders, and head injuries.
  • Research Tool: EEG is also used extensively in neuroscience research to study various cognitive processes, brain states, and the effects of interventions or stimuli on brain activity.

Think of it like this:

Imagine listening to a large group of people talking at a distance. You might not be able to understand any individual conversation, but you can still hear the general activity level - whether they're speaking loudly and excitedly, or quietly and calmly. EEG is similar; it doesn't pinpoint the activity of individual neurons, but it captures the collective electrical "chatter" of large groups of neurons.

In simple terms, EEG is a method of listening to the brain's electrical activity using sensors placed on the scalp.