Information content with low- vs. high-T_c SQUID arrays in MEG recordings: The case for high-T_c SQUID-based MEG

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• 作者：Justin F. Schneiderman
• 关键词：Channel capacity ; Total information ; High-Tc SQUID ; MEG ; SQUID-sensor arrays ; Neuroimaging
• 刊名：Journal of Neuroscience Methods
• 出版年：30 January, 2014
• 年：2014
• 卷：222
• 期：Complete
• 页码：42-46
• 全文大小：654 K

文摘

Background

Magnetoencephalography (MEG) is a method of studying brain activity via recordings of the magnetic field generated by neural activity. Modern MEG systems employ an array of low critical-temperature superconducting quantum interference devices (low-T_c SQUIDs) that surround the head. The geometric distribution of these arrays is optimized by maximizing the information content available to the system in brain activity recordings according to Shannon's theory of noisy channel capacity.

New method

Herein, we present a theoretical comparison of the performance of low- and high-T_c SQUID-based multichannel systems in recordings of brain activity.

Results

We find a high-T_c SQUID magnetometer-based multichannel system is capable of extracting at least 40% more information than an equivalent low-T_c SQUID system. The results suggest more information can be extracted from high-T_c SQUID MEG recordings (despite higher sensor noise levels than their low-T_c counterparts) because of the closer proximity to neural sources in the brain.

Comparison with existing methods

We have duplicated previous results in terms of total information of multichannel low-T_c SQUID arrays for MEG. High-T_c SQUID technology theoretically outperforms its conventional low-T_c counterpart in MEG recordings.

Conclusions

A full-head high-T_c SQUID-based MEG system's potential for extraction of more information about neural activity can be used to, e.g., develop better diagnostic and monitoring techniques for brain disease and enhance our understanding of the working human brain.