Helbling Saskia
Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main, Germany.
Imaging Neurosci (Camb). 2025 Jan 2;3. doi: 10.1162/imag_a_00410. eCollection 2025.
We explore the potential of optically pumped magnetometers (OPMs) to non-invasively infer the laminar origins of neural activity. OPM sensors can be positioned closer to the scalp than conventional cryogenic magnetoencephalography (MEG) sensors, opening an avenue to higher spatial resolution when combined with high-precision source space modelling. By simulating the forward model projection of single dipole sources at deep and superficial cortical surfaces onto OPM sensor arrays with varying sensor densities and measurement axes, and employing sparse source reconstruction approaches, we find that laminar inference with OPM arrays is possible at relatively low sensor counts under moderate-to-high signal-to-noise ratios (SNR). We observe improvements in laminar inference with increasing spatial sampling densities and measurement axes and demonstrate the advantage of placing the sensors closer to the scalp for inferring the laminar origins of cortical sources. However, challenges remain, such as biases towards both the superficial and deep surfaces at very low SNRs and a notable bias towards the deep surface when combining empirical Bayesian beamformer (EBB) source reconstruction with a whole-brain analysis. Adequate SNR through appropriate trial numbers and shielding, as well as precise co-registration, is crucial for reliable laminar inference with OPMs.
我们探讨了光泵磁力计（OPM）在无创推断神经活动层状起源方面的潜力。与传统的低温脑磁图（MEG）传感器相比，OPM传感器可以放置得更靠近头皮，当与高精度源空间建模相结合时，为实现更高的空间分辨率开辟了一条途径。通过模拟单偶极子源在深部和浅表皮质表面上向前模型投影到具有不同传感器密度和测量轴的OPM传感器阵列上，并采用稀疏源重建方法，我们发现，在中等到高信噪比（SNR）条件下，使用相对较少数量的传感器，OPM阵列就可以进行层状推断。我们观察到，随着空间采样密度和测量轴数量的增加，层状推断得到改善，并且证明了将传感器放置得更靠近头皮在推断皮质源层状起源方面的优势。然而，挑战依然存在，例如在极低SNR时对浅表和深部表面的偏差，以及在将经验贝叶斯波束形成器（EBB）源重建与全脑分析相结合时对深部表面的明显偏差。通过适当的试验次数和屏蔽获得足够的SNR，以及精确的配准，对于使用OPM进行可靠的层状推断至关重要。
