An MRI Compatible Data Acquisition Device for Rat Brain Recording Inside 16.4T Magnet

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Imaging

Background:

• Concurrent recording of neural activity and functional magnetic resonance imaging (fMRI) is crucial for understanding neurovascular coupling.
• Existing methods face challenges with electromagnetic interference (EMI) and artifacts in strong magnetic fields, limiting simultaneous data acquisition.
• Ultrahigh magnetic field (UMF) environments, such as 16.4 T, exacerbate these challenges for neural recording devices.

Purpose of the Study:

• To develop a novel, low-noise neural recorder chip and a compatible data acquisition (DAQ) device for simultaneous neural and fMRI recording.
• To design a system that is insensitive to radio frequency (RF) pulses and gradient echo artifacts in high magnetic fields.
• To improve the performance and reduce artifact impact in concurrent neuroimaging studies.

Main Methods:

• Designed a frequency-shaping based neural recorder chip optimized for low noise and MRI compatibility.
• Developed a multi-circuit optimized data acquisition (DAQ) device incorporating the neural recorder chip.
• Conducted bench-top noise measurements and animal experiments in an ultrahigh magnetic field (16.4 T) environment.

Main Results:

• The DAQ device exhibited low input-referred noise (4.5 μV from 300 Hz to 3000 Hz) with minimal EMI impact at 16.4 T.
• Successfully recorded local field potentials (LFPs) and extracellular spikes from rat brains during various MRI scanning modes.
• Demonstrated significant reduction in system recovery time after gradient artifacts (from >25 ms to <5 ms) and absence of obvious artifacts.

Conclusions:

• The proposed frequency-shaping neural recorder chip and DAQ device architecture are highly MRI compatible.
• The system achieves competitive performance for concurrent recording of neural activities and fMRI data, even in UMF.
• This technology facilitates advanced studies of neurovascular coupling by enabling robust simultaneous electrophysiological and hemodynamic recordings.