Tyson-Carr John, Bertamini Marco, Rampone Giulia, Jones Andrew, Makin Alexis D J
Department of Psychological Sciences, University of Liverpool, Liverpool, UK.
Department of Psychological Sciences, University of Liverpool, Liverpool, UK; Dipartimento di Psicologia Generale, Università di Padova, Padova, Italy.
Cortex. 2025 Mar;184:32-46. doi: 10.1016/j.cortex.2024.11.014. Epub 2024 Dec 14.
The human visual system is tuned to symmetry, and the neural response to visual symmetry has been well studied. One line of research measures an Event Related Potential (ERP) component called the Sustained Posterior Negativity (SPN). Amplitude is more negative at posterior electrodes when participants see symmetrical patterns compared to asymmetrical patterns. Source localization confirms that the SPN is generated by two dipoles in the left and right extrastriate cortex, in line with fMRI results. However, exploratory analysis by Tyson-Carr, Bertamini, Rampone, and Makin (2021) found a third symmetry response located approximately in the posterior cingulate peaking at around 600 msec. The third symmetry response was only generated in conditions where symmetry was 1) task relevant and 2) salient. We tested whether these findings are reliable by running source localization analysis on all suitable datasets from the complete Liverpool SPN catalogue (an online repository of all 40 SPN projects with 2215 participants https://osf.io/2sncj/). We predicted that less variance would be explained by a two-dipole model in experiments where participants classified regularity (hypothesis 1), and, when the third dipole is present, amplitude would correlate with that of the sensor-level SPN (hypothesis 2). Hypothesis 1 was not supported, while hypothesis 2 was. We conclude that the bilateral extrastriate symmetry response is sometimes followed by a third activation near the posterior cingulate. However, this third symmetry response is not as predictable as we had assumed. One possibility is that it may sometimes be hidden from average waveforms by temporal inconsistency between trials. This may happen more in experiments with longer presentation durations.
人类视觉系统对对称性很敏感，并且对视觉对称性的神经反应已经得到了充分研究。一项研究测量了一种称为持续后负波（SPN）的事件相关电位（ERP）成分。当参与者看到对称图案时，后电极处的振幅比看到不对称图案时更负。源定位证实，SPN是由左右纹外皮层中的两个偶极子产生的，这与功能磁共振成像（fMRI）结果一致。然而，泰森 - 卡尔、贝尔塔米尼、兰波内和马金（2021年）的探索性分析发现了第三个对称性反应，大约位于后扣带回，在600毫秒左右达到峰值。第三个对称性反应仅在对称性满足以下两个条件时产生：1）与任务相关，2）显著。我们通过对来自完整的利物浦SPN目录（一个包含2215名参与者的40个SPN项目的在线存储库https://osf.io/2sncj/）的所有合适数据集进行源定位分析，来测试这些发现是否可靠。我们预测，在参与者对规律性进行分类的实验中，双偶极子模型解释的方差会更小（假设1），并且当存在第三个偶极子时，其振幅将与传感器水平的SPN振幅相关（假设2）。假设1未得到支持，而假设2得到了支持。我们得出结论，双侧纹外对称性反应有时会伴随着后扣带回附近的第三次激活。然而，这个第三个对称性反应并不像我们假设的那样可预测。一种可能性是，它有时可能会因试验之间的时间不一致而从平均波形中隐藏起来。在呈现持续时间较长的实验中，这种情况可能更常发生。
