Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan.
Proyecto de Neurociencias, Facultad de Estudios Superiores Iztacala (FES-I), Universidad Nacional Autónoma de México, Tlalnepantla Estado de México, Mexico.
Sci Rep. 2018 Apr 11;8(1):5836. doi: 10.1038/s41598-018-23942-x.
Variability in neuronal response latency has been typically considered caused by random noise. Previous studies of single cells and large neuronal populations have shown that the temporal variability tends to increase along the visual pathway. Inspired by these previous studies, we hypothesized that functional areas at later stages in the visual pathway of face processing would have larger variability in the response latency. To test this hypothesis, we used magnetoencephalographic data collected when subjects were presented with images of human faces. Faces are known to elicit a sequence of activity from the primary visual cortex to the fusiform gyrus. Our results revealed that the fusiform gyrus showed larger variability in the response latency compared to the calcarine fissure. Dynamic and spectral analyses of the latency variability indicated that the response latency in the fusiform gyrus was more variable than in the calcarine fissure between 70 ms and 200 ms after the stimulus onset and between 4 Hz and 40 Hz, respectively. The sequential processing of face information from the calcarine sulcus to the fusiform sulcus was more reliably detected based on sizes of the response variability than instants of the maximal response peaks. With two areas in the ventral visual pathway, we show that the variability in response latency across brain areas can be used to infer the sequence of cortical activity.
神经元反应潜伏期的变化通常被认为是由随机噪声引起的。先前对单细胞和大神经元群体的研究表明，随着视觉通路的进展，时间变异性往往会增加。受这些先前研究的启发，我们假设在面部处理的视觉通路的后期功能区域中，反应潜伏期的变异性会更大。为了验证这一假设，我们使用了在给被试呈现人脸图像时采集的脑磁图数据。众所周知，人脸会引起从初级视觉皮层到梭状回的一系列活动。我们的结果表明，与距状裂相比，梭状回的反应潜伏期变异性更大。对潜伏期变异性的动态和频谱分析表明，在刺激开始后 70ms 到 200ms 之间以及在 4Hz 到 40Hz 之间，梭状回的反应潜伏期比距状裂的反应潜伏期更具变异性。基于反应变异性的大小，而不是最大反应峰的时刻，可以更可靠地检测到从距状沟到梭状沟的面部信息的顺序处理。通过对腹侧视觉通路中的两个区域进行研究，我们表明，跨脑区的反应潜伏期变异性可用于推断皮质活动的顺序。
