Skip to main content

EEG Recording Techniques: Electrode Placement (10-20 System)

 

EEG Recording Techniques: Electrode Placement (10-20 System)

Introduction to the 10-20 System

The 10-20 system is a standardized method for placing electrodes on the scalp to record brain electrical activity (EEG). It ensures consistency and comparability across different studies. The system is based on the distances between specific anatomical landmarks on the head.

Key Landmarks

Before placing electrodes, you need to identify the following landmarks:

  • Nasion: The bridge of the nose.
  • Inion: The most prominent point at the back of the head.
  • Preauricular points: The points just in front of the ear canals.

Electrode Placement

  1. Measure head circumference:

    • Measure the distance between the nasion and inion (A-P diameter).
    • Measure the distance between the preauricular points (L-R diameter).
    • The average of these two measurements is the head circumference.

  2. Calculate electrode positions:

    • The 10-20 system is based on percentages of the head circumference.
    • For example, Fp1 and Fp2 are placed at 10% of the A-P distance from the nasion.
    • Fz is placed at 20% of the A-P distance from Fp1.
    • Other electrodes are placed similarly based on their designated percentages.

  3. Identify electrode positions:

    • Electrodes are named based on their location:
      • F: Frontal lobe
      • C: Central lobe
      • P: Parietal lobe
      • O: Occipital lobe
      • T: Temporal lobe
      • A: Auricular (ear)
      • Z: Zero line (midline)
      • Odd numbers: Left hemisphere
      • Even numbers: Right hemisphere
    • Example: Fp1 is the frontal pole electrode on the left hemisphere.

  4. Place electrodes:

    • Clean the scalp to remove hair and oil.
    • Apply electrode paste to the electrode and the scalp.
    • Secure the electrode in place using a cap or tape.

Common Electrode Configurations

While the 10-20 system provides a standard, there are different electrode configurations depending on the specific research or clinical application. Some common configurations include:

  • 19-channel EEG: Used for basic EEG recordings.
  • 32-channel EEG: Provides more detailed information about brain activity.
  • 64-channel EEG: Offers high-resolution EEG data.

Additional Considerations

  • Impedance: The resistance between the electrode and the scalp should be low for optimal signal quality.
  • Ground electrode: A ground electrode is often placed on the forehead or mastoid to reduce noise.
  • Reference electrode: The reference electrode can be placed at various locations, such as linked ears, average reference, or a specific electrode.
  • Artifact reduction: Techniques like filtering and averaging can help reduce noise and artifacts in the EEG signal.

Comments

Post a Comment

Popular posts from this blog

Non-invasive BCIs (EEG-based)

  This is an exciting and rapidly developing field within neurotechnology. 1. Introduction to Non-invasive BCIs:    - Definition and basic concepts    - Advantages over invasive BCIs    - Historical development 2. Principles of Electroencephalography (EEG):    - Neural origins of EEG signals    - Frequency bands (delta, theta, alpha, beta, gamma)    - Spatial and temporal resolution 3. EEG Recording Techniques:    - Electrode placement (10-20 system)    - Types of electrodes (wet, dry, active)    - Amplification and digitization of signals    - Artifact reduction techniques 4. Signal Processing in EEG-based BCIs:    - Preprocessing (filtering, artifact removal)    - Feature extraction methods:      * Time-domain features      * Frequency-domain features      * Time-frequency analysis      * Spatial filter...
1 comment
Read more

Tumors of the Nervous System complete tutorial

Tumors of the nervous system can be classified into two broad categories: primary tumors, which originate in the nervous system, and secondary tumors, which originate elsewhere in the body and spread to the nervous system. Primary tumors of the nervous system can be further divided into benign (non-cancerous) and malignant (cancerous) tumors. **Benign Tumors of the Nervous System:** 1. **Meningiomas**: These are the most common type of benign brain tumor. They arise from the meninges, the membranes that surround the brain and spinal cord. 2. **Schwannomas**: These tumors arise from Schwann cells, which produce the myelin sheath that surrounds and insulates nerve fibers. 3. **Neuromas**: These are benign tumors that arise from nerve tissue. 4. **Pituitary Adenomas**: These are benign tumors that arise from the pituitary gland, a small gland at the base of the brain that produces hormones. 5. **Craniopharyngiomas**: These are benign tumors that arise near the pituitary gland. ...
Post a Comment
Read more

Neuralink History

Neuralink, founded by Elon Musk in 2016, has been at the forefront of developing brain-computer interface (BCI) technology, aiming to create a seamless connection between the human brain and computers. The company's journey has been marked by significant milestones, challenges, and breakthroughs. In 2019, Neuralink introduced its first prototype, a device that could record and stimulate brain activity. This was followed by the development of a robot capable of performing the delicate surgery required for implanting the device. The robot's design was a collaboration between Neuralink and Woke Studios, showcasing the company's commitment to innovation. In January 2024, Neuralink achieved a major milestone when it announced the successful implantation of its brain-computer interface in a human subject. This marked the beginning of a new era in BCI technology, as the device allowed the subject to control a computer mouse using their thoughts. The company has since continue...
Post a Comment
Read more