Meng Shuang, Oi Misato, Saito Godai, Saito Hirofumi
Department of Cognitive and Psychological Science, Graduate School of Informatics, Nagoya University, Nagoya, Japan.
Faculty of Arts and Science, Kyushu University, Fukuoka, Japan.
PLoS One. 2017 Sep 1;12(9):e0183818. doi: 10.1371/journal.pone.0183818. eCollection 2017.
Previous studies, mainly using a first-person perspective (1PP), have shown that the judgments of the hand laterality judgment (HLJ) task are dependent on biomechanical constraints (BC). Specifically, differing reaction times (RT) for hand pictures rotated medially or laterally around the mid sagittal plane are attributed to the BC effect on motor imagery. In contrast, we investigated whether the HLJ task is also subject to BC when performed from a third-person perspective (3PP) as well as 1PP using near-infrared spectroscopy (NIRS) to measure the brain activity of prefrontal cortex (PFC) in right-handed participants assigned to 1PP or 3PP groups. The 1PP group judged whether a presented hand was their own left or right hand, and the 3PP group whether it was the other's left or right hand. Using their HLJ task error rates, the 1PP and 3PP groups were subdivided into an Error Group (EG) and No Error Group (NEG). For the 1PP group, both EG and NEG showed a significant Hand Laterality × Orientation interaction for RT, indicating the BC effect on motor imagery. For the 3PP group, however, neither EG nor NEG showed the interaction, even though EG showed a significantly longer RT than NEG. These results suggest that the 3PP EG appropriately followed the 3PP task instruction, while the NEG might have taken 1PP. However, the 3PP EG NIRS profile of left PFC showed a significant Hand Laterality × Orientation interaction, while the 1PP EG did not. More noteworthy is that the left PFC activation of EG showed an interaction between the 1PP and 3PP groups when the left hand was presented. Furthermore, in the NEG, the PFC activation was not influenced by the BC in either the 1PP or 3PP condition. These results indicate that BC interferes with the HLJ task performed from the 1PP and 3PP.
以往的研究主要采用第一人称视角（1PP），结果表明，手的偏侧性判断（HLJ）任务的判断取决于生物力学限制（BC）。具体而言，围绕矢状面中线向内或向外旋转的手部图片的不同反应时间（RT）归因于BC对运动想象的影响。相比之下，我们研究了在使用近红外光谱（NIRS）测量分配到1PP或3PP组的右利手参与者前额叶皮层（PFC）的大脑活动时，从第三人称视角（3PP）以及1PP执行HLJ任务时是否也受BC影响。1PP组判断呈现的手是他们自己的左手还是右手，3PP组判断是对方的左手还是右手。利用他们的HLJ任务错误率，将1PP组和3PP组细分为错误组（EG）和无错误组（NEG）。对于1PP组，EG和NEG在RT上均显示出显著的手偏侧性×方向交互作用，表明BC对运动想象有影响。然而，对于3PP组，EG和NEG均未显示出这种交互作用，尽管EG的RT显著长于NEG。这些结果表明，3PP的EG适当地遵循了3PP任务指令，而NEG可能采用了1PP。然而，3PP的EG左前额叶皮层的NIRS特征显示出显著的手偏侧性×方向交互作用，而1PP的EG则没有。更值得注意的是，当呈现左手时，EG的左前额叶皮层激活在1PP组和3PP组之间显示出交互作用。此外，在NEG中，PFC激活在1PP或3PP条件下均不受BC影响。这些结果表明，BC会干扰从1PP和3PP执行的HLJ任务。
