Recording brain activities in unshielded Earth's field with optically pumped atomic magnetometers

Area of Science:

• Neuroscience
• Biophysics
• Medical Instrumentation

Background:

• Magnetoencephalography (MEG) is crucial for diagnosing brain disorders by mapping neural activity.
• Traditional MEG requires magnetically shielded rooms, limiting its portability and accessibility.
• Optically pumped atomic magnetometers offer high sensitivity for magnetic field detection.

Purpose of the Study:

• To develop and demonstrate an unshielded MEG system using optically pumped atomic magnetometers.
• To overcome the limitations of conventional shielded MEG systems.
• To explore the potential for a practical, wearable, and movable MEG system.

Main Methods:

• Construction of an atomic magnetic gradiometer.
• Implementation of feedback methods to mitigate environmental magnetic field noise.
• Utilizing optically pumped atomic magnetometers for neural signal detection.

Main Results:

• Successful detection of alpha rhythm signals associated with eye closure in an unshielded environment.
• Clear observation of auditory evoked field signals under Earth's magnetic field.
• Demonstration of noise reduction techniques for unshielded operation.

Conclusions:

• The developed unshielded MEG system is effective in detecting neural signals.
• This technology holds promise for creating practical, wearable, and movable MEG devices.
• The system offers new possibilities for medical diagnosis of brain conditions.