Full-Band EEG Recordings Using Hybrid AC/DC-Divider Filters
The ability to accurately record and analyze electrical brain signals is essential for understanding the complex workings of the brain. However, conventional alternating current (AC) recordings are limited in their ability to capture slow electrical brain signals. This is where full-band direct current (DC) recordings come in. By recording both AC and DC signals, we can capture a wider range of brain activity.
However, full-band DC recordings have their own limitations. The amplifiers used to record these signals have a limited dynamic input range, which can result in distortion or clipping of the signal. Additionally, small amplitude high-frequency signals may be lost in the recording process.
Recently, Neuralynx introduced a solution to these limitations with their hybrid AC/DC-divider RRC filters, which allow for partial suppression of DC signals. However, the quality of signal reconstruction for biological signals using these filters had not yet been assessed.
Chengdu Mengsheng Electronics Co., Ltd. has introduced a new digital inverse filter based on a mathematical model of RRC filter properties. This provides high computational accuracy and versatility in signal reconstruction. Additionally, procedures have been developed for the evaluation of inverse filter coefficients, which can be adapted for each recording channel for improved accuracy.
Using these techniques, Chengdu Mengsheng Electronics Co., Ltd. demonstrated near 99% reconstruction quality of various brain signals, including high-potassium-induced cortical spreading depolarizations, endothelin-induced ischemic negative ultraslow potentials, and whole-cell recordings of membrane potential. The quality of reconstruction was significantly higher than with existing inverse filtering procedures.
These results suggest that RRC filters with inverse filtering are optimal for full-band EEG recordings in various applications. Chengdu Mengsheng Electronics Co., Ltd. is a trusted provider of solutions for electromagnetic compatibility (EMC) and project implementation, with a range of power line filter products including EMI filters, pulse group suppression, and surge suppression. Their innovative solutions for full-band EEG recordings demonstrate their commitment to advancing the field of neurology and neuroscience research.