Department of Psychiatry and Psychotherapy, University of Regensburg, Universitaetsstrasse 84, Regensburg 93053, Germany.
Department of Psychiatry and Psychotherapy, Faculty of Medicine, RWTH Aachen University, Templergraben 55, Aachen 52062, Germany.
J Sex Med. 2024 Oct 31;21(11):1004-1010. doi: 10.1093/jsxmed/qdae122.
Motor cortex excitability may represent the neuronal endpoint of motivational processes and was shown to be modulated by both sexual arousal and deceptive behavior.
This is the first study to investigate the influence of lying and sex in heterosexual women and men based on motor-evoked potentials (MEPs) measured while viewing sexually arousing pictures.
Sixteen heterosexual couples were shown 360 trials consisting of pictures displaying both almost naked females and males and neutral control images. In a subsequent forced-choice question about wanting to see the respective pictures fully naked, they were instructed to either answer in agreement with or opposite to their sexual preference. Participants went through 2 blocks of answering truthfully and 2 blocks of lying, with these 4 blocks being shown in a randomized alternating order.
To measure cortical excitability, MEPs were used, evoked by single transcranial magnetic stimulation pulses between image presentation and response.
In normalized MEPs, women and men showed higher amplitudes for preferred over non-preferred sexual stimuli, but only on a descriptive level. Planned contrasts showed higher non-normalized MEPs for lying in all picture categories. Direct comparisons to a preliminary study showed overall lower effect sizes.
Both sexes tend to show higher MEPs in response to their sexually preferred stimuli. MEPs are not stable markers for willful volitionally controlled deception although lying does increase cortical excitability. The present experimental design does not seem valid enough to serve as a diagnostic marker for sexual preference or paraphilia and malingering.
This is the first study investigating whether sexual motivational stimuli modulate MEPs in women, while also examining the influence of lying for both sexes. The sample was too small for some found effects to be significant. Also, the experimental setup may have been less suited for female participants in comparison to male ones.
The operationalization of sexual motivation via MEPs seems to highly depend on different experimental factors including the sex of the participants, induced motivation, and lying.
运动皮层兴奋性可能代表了动机过程的神经元终点，并且已经证明它可以被性唤起和欺骗行为所调节。
这是第一项研究，旨在基于观看性唤起图片时测量的运动诱发电位（MEPs），调查性别的欺骗行为对异性恋女性和男性的影响。
16 对异性恋夫妇观看了 360 个试验，其中包括展示几乎裸体女性和男性的图片以及中性对照图像。在随后的关于是否想看各自图片全裸的强制性选择问题中，他们被指示回答与他们的性偏好一致或相反。参与者经历了 2 个诚实回答的模块和 2 个说谎的模块，这 4 个模块以随机交替的顺序显示。
为了测量皮层兴奋性，在图像呈现和反应之间使用单磁刺激脉冲诱发 MEPs。
在归一化 MEPs 中，女性和男性对偏好的性刺激表现出比非偏好刺激更高的振幅，但仅在描述性水平上。计划对比显示，在所有图片类别中，说谎时的非归一化 MEPs 更高。与初步研究的直接比较显示，总体而言，较小的效应量。
两种性别在对其性偏好刺激的反应中均表现出更高的 MEPs。尽管说谎确实会增加皮层兴奋性，但 MEPs 并不是自愿控制欺骗的稳定标志物。目前的实验设计似乎不够有效，不能作为性偏好或性变态和伪装的诊断标志物。
这是第一项研究，调查了性动机刺激是否会在女性中调节 MEPs，同时还研究了两性说谎的影响。对于一些发现的影响，样本太小而无法显著。此外，与男性参与者相比，实验设置可能对女性参与者不太合适。
通过 MEPs 操作化的性动机似乎高度依赖于不同的实验因素，包括参与者的性别、诱导的动机和说谎。
