In the approach of frequency tagging, stimuli that are presented periodically generate periodic responses of the brain. Following a transformation into the frequency domain, the brain's response is often evident at the frequency of stimulation, F, and its higher harmonics (2F, 3F, etc.). This approach is increasingly used in neuroscience, as it affords objective measures to characterize brain function. However, whether these specific harmonic frequency responses should be combined for analysis—and if so, how—remains an outstanding issue. In most studies, higher harmonic responses have not been described or were described only individually; in other studies, harmonics have been combined with various approaches, for example, averaging and root-mean-square summation. A rationale for these approaches in the context of frequency-based analysis principles and an understanding of how they relate to the brain's response amplitudes in the time domain have been missing. Here, with these elements addressed, the summation of (baseline-corrected) harmonic amplitude is recommended.

在频率标记方法中，周期性呈现的刺激会产生大脑的周期性反应。在转换到频域之后，大脑的反应通常在刺激频率F及其高次谐波 (2 F , 3 F， 等等。）。这种方法越来越多地用于神经科学，因为它提供了表征大脑功能的客观措施。然而，这些特定的谐波频率响应是否应该结合起来进行分析——如果是，如何结合——仍然是一个悬而未决的问题。在大多数研究中，没有描述或仅单独描述高次谐波响应；在其他研究中，谐波已与各种方法相结合，例如平均和均方根求和。这些方法在基于频率的分析原理的背景下的基本原理以及对它们如何与时域中大脑的响应幅度相关的理解已经缺失。在这里，针对这些要素，建议对（基线校正的）谐波幅度求和。