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EEG brain waves reveal the mystery: How to capture the brain's electrical signals?
Electroencephalography (EEG) is an electrographic method that records the brain's spontaneous electrical activity. The non-invasive nature of this technology makes it an indispensable tool in neuroscience and clinical medicine. EEG can accurately capture the electrical signals of brain neurons and provide valuable information about an individual's state of consciousness and brain function. To date, EEG has been widely used in the diagnosis of epilepsy, sleep disorders and other types of neurological diseases.
The development and application of EEG technology shows how the brain works and helps us gain a deeper understanding of human neural activity.
Basic principles of EEG
EEG uses electrodes on the scalp to record the electrical signals of neurons. These signals reflect postsynaptic potentials of neurons in the neocortex and the paleocortex. Electrodes are mounted according to the international 10-20 system, which enables EEG to provide consistent recordings in clinical and research settings.
EEG measures voltage fluctuations generated by neuronal activity, which is affected by the scalp, skull, and other intervening tissues, so electrodes in different locations can sense different signals. Generally speaking, EEG is particularly good at reflecting the activity of cortical neurons close to the electrodes, while deeper structures farther away, such as the hippocampus and thalamus, are difficult to capture.
EEG frequency range
The EEG of a healthy adult will show different waveforms that are related to the individual's level of wakefulness. The frequency range of EEG is between 1 and 30 Hz, and the various waveforms include:
- Alpha waves (8-13 Hz): Associated with a relaxed and wakeful state, they are usually most pronounced in the parietal and occipital lobes.
- Beta waves (13-30 Hz): occur during periods of intense mental activity and are mainly distributed in the frontal lobe and other areas.
- Theta waves (4-7 Hz): usually appear in light sleep state.
- Delta waves (0.5-4 Hz): more common in deep sleep.
The diversity of EEG not only enables the identification of different mental states, but also provides new insights into cognitive science and neuromedicine.
Clinical Applications
EEG is the gold standard for epilepsy diagnosis. It can detect abnormal electrical activity, such as sharp waves and spikes, and can be used to determine the type and frequency of epilepsy. When an EEG shows abnormal activity, this essentially confirms the presence of epilepsy. Additionally, EEG can help diagnose sleep disorders, brain death, and in some cases predict how a patient will recover.
In the epilepsy monitoring unit (EMU), EEG can be continuously recorded during a patient's seizure, which is crucial for understanding the characteristics of the seizure and the area of lesions.
Research and application of electroencephalogram
EEG technology is also widely used in neuroscience and cognitive research, especially in studying human functions such as swallowing and other neuropsychological processes. This technology is not only limited to clinical applications, but has also become an important tool in cognitive science. For example, by analyzing event-related potentials (ERPs), researchers can explore how the brain processes visual or auditory stimuli.
Advantages and Disadvantages of EEGThe application scope of EEG is constantly expanding, and its value in the study of neural mechanisms is becoming increasingly prominent.
Compared with functional magnetic resonance imaging (fMRI), positron emission tomography (PET), and other methods, EEG has many advantages: low cost, high accessibility, and high temporal resolution, making it an ideal method for neuroscience research and An important tool in clinical diagnosis. However, its low spatial resolution means there can be challenges in identifying signals in specific areas of the brain.
Although EEG has its limitations in measuring and interpreting neural signals, scientists continue to explore and study how to overcome these obstacles.
Closing Thoughts
No matter how EEG technology evolves, how it helps us better understand the relationship between human consciousness and behavior remains a major challenge for scientific research. How do these electrical signals reveal the deepest secrets of our inner selves?
