Carrubba Simona, Frilot Clifton, Chesson Andrew L, Marino Andrew A
Department of Orthopaedic Surgery, LSU Health Sciences Center, Shreveport, LA 71130-3932, USA.
Neurosci Lett. 2007 May 1;417(2):212-6. doi: 10.1016/j.neulet.2007.02.046. Epub 2007 Feb 22.
Recent electrophysiological evidence suggested the existence of a human magnetic sense, but the kind of dynamical law that governed the stimulus-response relationship was not established. We tested the hypothesis that brain potentials evoked by the onset of a weak, low-frequency magnetic field were nonlinearly related to the stimulus. A field of 1G, 60 Hz was applied for 2s, with a 5s inter-stimulus period, and brain potentials were recorded from occipital electrodes in eight subjects, each of whom were measured twice, with at least 1 week between measurements. The recorded signals were subjected to nonlinear (recurrence analysis) and linear (time averaging) analyses. Using recurrence analysis, magnetosensory evoked potentials (MEPs) were detected in each subject in both the initial and replicate studies, with one exception. All MEPs exhibited the expected latency but differed in dynamical characteristics, indicating that they were nonlinearly related to the stimulus. MEPs were not detected using time averaging, thereby further confirming their nonlinearity. Evolutionarily conditioned structures that help mediate linear field-transduction in lower life forms may be expressed and functionally utilized in humans, but in a role where they facilitate vulnerability to man-made environmental fields.
最近的电生理证据表明人类存在磁感，但尚未确定支配刺激-反应关系的动力学规律。我们检验了这样一个假设，即微弱低频磁场开始时诱发的脑电势与刺激呈非线性关系。施加1G、60Hz的磁场2秒，刺激间隔为5秒，从8名受试者的枕叶电极记录脑电势，每名受试者测量两次，测量间隔至少1周。对记录的信号进行非线性（递归分析）和线性（时间平均）分析。使用递归分析，在初始研究和重复研究中，除一名受试者外，其他每名受试者均检测到磁感觉诱发电位（MEP）。所有MEP均表现出预期的潜伏期，但动力学特征不同，表明它们与刺激呈非线性关系。使用时间平均未检测到MEP，从而进一步证实了它们的非线性。在较低生命形式中有助于介导线性场转导的进化条件结构可能在人类中得以表达并发挥功能作用，但在这种作用中，它们会使人更容易受到人造环境场的影响。
