Kaluzny P, Palmeri A, Wiesendanger M
Institut de Physiologie, Université de Fribourg, Switzerland.
Electroencephalogr Clin Neurophysiol. 1994 Dec;93(6):450-8. doi: 10.1016/0168-5597(94)90153-8.
The properties of the sensorimotor system controlling finger movements were investigated in the simple uni- and bimanual reaction time (RT) paradigm, with emphasis on the problem of interhemispheric transfer of sensory and motor information. Unimanual and bimanual responses of the index fingers were elicited by stimulation of either left or right hand and resulting reaction times were compared to assess the degree of right-left differences and thus also of crossed-uncrossed differences (CUD). The response consisted of a force pulse (first dorsal interosseus muscle) which was elicited by a non-painful electrical stimulus applied to the base of the middle finger. In unimanual experiments, the population analysis showed that RTs obtained with contralateral stimuli were significantly longer (6 msec) than RTs elicited with ipsilateral stimuli. However, inter-subject differences were large and sometimes pointed in the non-expected direction (crossed < uncrossed). Statistically significant right-left differences in RT were detected in the bimanual response paradigm, but these differences occurred in both directions with the crossed RT either longer or shorter than uncrossed RT. The analysis of the correlation structure of bimanual RT suggested the presence of stimulus-related asymmetries of the hands. These observations provide some support for the notion of an additional processing time related to interhemispheric transmission of sensory and/or motor signals. In addition, it turned out that factors other than callosal transmission can also produce asymmetries in RTs of the two hands. Thus some subjects had consistent right-left differences which were unrelated to callosal transmission. Asymmetries were also introduced by changing the stimulation side. In the light of this multi-factorial influence, we argue that the underlying mechanisms leading to intermanual asymmetries in RT cannot be attributed exclusively to callosal transmission.
在简单的单双手反应时（RT）范式中，研究了控制手指运动的感觉运动系统的特性，重点关注感觉和运动信息的半球间传递问题。通过刺激左手或右手来引发食指的单手和双手反应，并比较由此产生的反应时间，以评估左右差异的程度，进而评估交叉-非交叉差异（CUD）的程度。反应由施加于中指根部的非疼痛性电刺激引发的力脉冲（第一背侧骨间肌）组成。在单手实验中，总体分析表明，对侧刺激获得的反应时明显长于同侧刺激引发的反应时（长6毫秒）。然而，个体间差异很大，有时指向非预期方向（交叉<非交叉）。在双手反应范式中检测到反应时存在统计学上显著的左右差异，但这些差异在两个方向上都有出现，交叉反应时可能长于或短于非交叉反应时。对双手反应时相关结构的分析表明，双手存在与刺激相关的不对称性。这些观察结果为与感觉和/或运动信号半球间传递相关的额外处理时间这一概念提供了一些支持。此外，结果表明，除胼胝体传递外的其他因素也会导致双手反应时出现不对称性。因此，一些受试者存在与胼胝体传递无关的一致的左右差异。改变刺激侧也会引入不对称性。鉴于这种多因素影响，我们认为导致反应时双手间不对称性的潜在机制不能完全归因于胼胝体传递。
