Nativ A, Pratt H, Allard F, Frank J S
Department of Kinesiology, University of Waterloo, Ontario.
Cortex. 1992 Sep;28(3):435-44. doi: 10.1016/s0010-9452(13)80153-0.
Measures reflecting central processing of somatosensory stimulation were recorded in left- and in right-handed subjects in order to evaluate differences between the two handedness groups in the vertical, rather than lateral, axis of processing. Somatosensory evoked potentials were recorded in left- and right-handers following electrical stimulation of the median nerve at the wrist. The relative vertical balance of processing was probed by comparing the amplitudes of the underlying activity in early evoked potentials, presumably originating subcortically, with later, cortically originating potentials. Central conduction time (CCT) of the sensory volleys was also recorded. The data revealed higher amplitude ratios (ARs) between subcortical and cortical potentials, as well as shorter CCTs, in left-handers. These results demonstrate that transmission differences between the handedness groups may occur early in central nervous system (CNS) conductance. The results are further discussed in light of evidence suggesting that stronger reliance on a subcortical mode of processing may underlie phenomenon of left-handedness.
为了评估在垂直（而非横向）加工轴上，两组惯用手人群之间的差异，对左利手和右利手受试者记录了反映体感刺激中枢加工的指标。在手腕处对正中神经进行电刺激后，记录了左利手和右利手受试者的体感诱发电位。通过比较早期诱发电位（可能起源于皮层下）与后期起源于皮层的电位中基础活动的振幅，探究了加工过程的相对垂直平衡。还记录了感觉冲动的中枢传导时间（CCT）。数据显示，左利手受试者皮层下和皮层电位之间的振幅比（AR）更高，CCT也更短。这些结果表明，在中枢神经系统（CNS）传导的早期，不同惯用手人群之间可能就存在传导差异。鉴于有证据表明，对皮层下加工模式的更强依赖可能是左利手现象的基础，对这些结果进行了进一步讨论。
