Electroencephalogram (EEG)

Definition

An electroencephalogram (EEG) is a test that measures electrical activity in the brain using electrodes placed on the scalp. This technique captures brainwave patterns, which are essential for understanding neural function and diagnosing conditions such as epilepsy and sleep disorders. The signal characteristics obtained from EEG can provide valuable information about the timing and intensity of brain activity, making it a crucial tool in both clinical and research settings.

5 Must Know Facts For Your Next Test

1. EEG records brain activity by detecting voltage fluctuations resulting from ionic current flows within the neurons of the brain.
2. The data from EEG can be analyzed in terms of frequency, amplitude, and phase to understand various mental states and cognitive functions.
3. Different states of consciousness, such as wakefulness, sleep, and relaxation, produce distinct EEG patterns that can be used to assess brain function.
4. EEG is non-invasive and typically painless, making it a widely used method for studying brain function without significant risk to patients.
5. The temporal resolution of EEG is high, allowing for the capture of rapid changes in brain activity on the order of milliseconds.

Review Questions

• How does the EEG measure electrical activity in the brain, and what are its main signal characteristics?
  • EEG measures electrical activity by placing electrodes on the scalp that detect voltage changes due to neural activity. The main signal characteristics include frequency (the speed of oscillations), amplitude (the strength of the signals), and phase relationships between different waveforms. These characteristics help identify various mental states and cognitive processes, providing insights into how the brain functions during different activities.
• Discuss the significance of analyzing different types of brainwaves recorded by EEG in understanding human behavior.
  • Analyzing different types of brainwaves—such as alpha, beta, theta, and delta—allows researchers to correlate specific patterns with various mental states and behaviors. For instance, increased alpha waves are often associated with relaxation, while beta waves are linked to active thinking and problem-solving. By understanding these connections, researchers can better grasp how changes in brain activity impact cognition and emotional well-being.
• Evaluate the impact of artifacts on EEG readings and how they can affect the interpretation of brain activity.
  • Artifacts can significantly impact EEG readings by introducing noise that obscures true neural signals. Common sources of artifacts include muscle contractions, eye movements, or external electrical interference. Understanding how to identify and minimize these artifacts is crucial for accurately interpreting EEG data. If artifacts are not properly addressed, they can lead to misdiagnosis or misunderstanding of a patient’s neurological condition.

Related terms

Brainwaves: Electrical impulses in the brain that result from the activity of neurons, categorized into different types such as alpha, beta, theta, and delta waves.

Neurofeedback:

A type of biofeedback that uses real-time displays of brain activity to teach self-regulation of brain function.

Artifact: Any noise or distortion in EEG signals that is not related to brain activity, often caused by movement, muscle contractions, or electrical interference.