Objective . Functional magnetic resonance imaging (fMRI) is commonly used to measure brain activity through the blood oxygen level dependent (BOLD) signal mechanism, but this only provides an indirect proxy signal to neuronal activity. Magnetoencephalography (MEG) provides a more direct measurement of the magnetic fields created by neuronal currents in the brain, but requires very specialized hardware and only measures these fields at the scalp. Recently, progress has been made to directly detect neuronal fields with MRI using the stimulus-induced rotary saturation (SIRS) effect, but interference from the BOLD response complicates such measurements. Here, we describe an approach to detect nanotesla-level, low-frequency alternating magnetic fields with an ultra-low field (ULF) MRI scanner, unaffected by the BOLD signal. Approach . A steady-state implementation of the stimulus-induced rotary saturation (SIRS) method is developed. The method is designed to generate a s...

中文翻译：

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使用稳态SIRS和超低场MRI检测纳特斯拉交流磁场。

目标。功能磁共振成像（fMRI）通常用于通过血氧水平依赖性（BOLD）信号机制来测量大脑活动，但这仅提供神经元活动的间接代理信号。磁脑电图（MEG）可以更直接地测量大脑中神经元电流产生的磁场，但是需要非常专业的硬件，并且只能在头皮上测量这些磁场。最近，已经取得了使用刺激诱导的旋转饱和度（SIRS）效应通过MRI直接检测神经元区域的进展，但是来自BOLD响应的干扰使此类测量变得复杂。在这里，我们描述了一种用超低场（ULF）MRI扫描仪检测纳米特斯拉级，低频交变磁场的方法，该方法不受BOLD信号的影响。方法。开发了稳态诱导旋转饱和度（SIRS）方法的实现方案。该方法旨在生成一个...