Cabral-Calderin Yuranny, Henry Molly J
Max Planck Institute for Empirical Aesthetics, Frankfurt am Main, Germany.
Toronto Metropolitan University, Toronto, Canada.
PLoS Biol. 2025 Jun 5;23(6):e3003180. doi: 10.1371/journal.pbio.3003180. eCollection 2025 Jun.
Neural tracking (entrainment) of auditory rhythms enhances perception. We previously demonstrated that transcranial alternating current stimulation (tACS) can enhance or suppress entrainment to rhythmic auditory stimuli, depending on the timing between the electrical and auditory signals, although tACS effects are primarily modulatory. This study further investigated entrainment to tACS and auditory rhythms when the electrical and auditory signals were presented together (Experiment 1, N = 34) or independently (Experiment 2, N = 24; Experiment 3, N = 12). We hypothesized that tACS effects would be more pronounced when the auditory rhythm was made less perceptually salient to reduce the competition with the electrical rhythm. Participants detected silent gaps in modulated or unmodulated noise stimuli. In Experiment 1, auditory stimuli predominated in entraining behavior. While behavioral entrainment to sound rhythms was affected by the modulation depth of the auditory stimulus, entrainment to tACS was not. In Experiment 2, with no rhythmic information from the sound, 17 of 24 participants showed significant behavioral entrainment to tACS, although the most effective tACS frequency varied across participants. An oscillator model with a free parameter for the individual resonance frequency produced profiles similar to those we observed behaviorally. In Experiment 3, both neural and behavioral entrainment to rhythmic sounds were affected by the auditory stimulus frequency, but again the most effective entraining frequency varied across participants. Our findings suggest that tACS effects depend on the individual's preferred frequency when there is no competition with sensory stimuli, emphasizing the importance of targeting individual frequencies in tACS experiments. When both sensory and electrical stimuli are rhythmic and compete, sensory stimuli prevail, indicating the superiority of sensory stimulation in modulating behavior.
听觉节律的神经追踪（夹带）可增强感知。我们之前证明，经颅交流电刺激（tACS）可增强或抑制对节律性听觉刺激的夹带，这取决于电信号和听觉信号之间的时间关系，尽管tACS的作用主要是调节性的。本研究进一步探究了在电信号和听觉信号同时呈现（实验1，N = 34）或独立呈现（实验2，N = 24；实验3，N = 12）时对tACS和听觉节律的夹带情况。我们假设，当听觉节律在感知上不那么突出以减少与电节律的竞争时，tACS的效果会更明显。参与者检测调制或未调制噪声刺激中的静音间隙。在实验1中，听觉刺激在夹带行为中占主导地位。虽然对声音节律的行为夹带受听觉刺激的调制深度影响，但对tACS的夹带不受影响。在实验2中，没有来自声音的节律信息，24名参与者中有17名表现出对tACS的显著行为夹带，尽管最有效的tACS频率在参与者之间有所不同。一个具有个体共振频率自由参数的振荡器模型产生的轮廓与我们行为观察到的相似。在实验3中，对节律性声音的神经和行为夹带都受听觉刺激频率的影响，但同样，最有效的夹带频率在参与者之间有所不同。我们的研究结果表明，在没有与感觉刺激竞争时，tACS的效果取决于个体的偏好频率，这强调了在tACS实验中针对个体频率的重要性。当感觉刺激和电刺激都是节律性的且相互竞争时，感觉刺激占主导，表明感觉刺激在调节行为方面的优越性。
