University of Haifa.
J Cogn Neurosci. 2020 May;32(5):762-782. doi: 10.1162/jocn_a_01550. Epub 2020 Feb 21.
Recent evidence suggests that during numerical calculation, symbolic and nonsymbolic processing are functionally distinct operations. Nevertheless, both roughly recruit the same brain areas (spatially overlapping networks in the parietal cortex) and happen at the same time (roughly 250 msec poststimulus onset). We tested the hypothesis that symbolic and nonsymbolic processing are segregated by means of functionally relevant networks in different frequency ranges: high gamma (above 50 Hz) for symbolic processing and lower beta (12-17 Hz) for nonsymbolic processing. EEG signals were quantified as participants compared either symbolic numbers or nonsymbolic quantities. Larger EEG gamma-band power was observed for more difficult symbolic comparisons (ratio of 0.8 between the two numbers) than for easier comparisons (ratio of 0.2) over frontocentral regions. Similarly, beta-band power was larger for more difficult nonsymbolic comparisons than for easier ones over parietal areas. These results confirm the existence of a functional dissociation in EEG oscillatory dynamics during numerical processing that is compatible with the notion of distinct linguistic processing of symbolic numbers and approximation of nonsymbolic numerical information.
最近的证据表明，在数值计算过程中，符号和非符号处理是两种功能不同的操作。然而，两者大致都募集了相同的大脑区域（顶叶皮层中的空间重叠网络），并且几乎同时发生（刺激后大约 250 毫秒）。我们通过不同频率范围的功能相关网络来测试符号和非符号处理是否分离的假设：符号处理的高伽马（高于 50 Hz）和非符号处理的低贝塔（12-17 Hz）。当参与者比较符号数字或非符号数量时，对 EEG 信号进行了量化。在前额中央区域，对于更困难的符号比较（两个数字之间的比值为 0.8），观察到比更容易的比较（比值为 0.2）更大的 EEG 伽马频带功率。类似地，在顶叶区域，对于更困难的非符号比较，观察到比更容易的比较更大的β频带功率。这些结果证实了在数值处理过程中，EEG 振荡动力学存在功能分离，这与符号数字的不同语言处理和非符号数值信息的近似的概念是一致的。
