Björkman Anders, Rosén Birgitta, Lundborg Göran
Department of Hand Surgery, University Hospital Malmö, SE-20502 Malmö, Sweden.
Eur J Neurosci. 2004 Nov;20(10):2733-6. doi: 10.1111/j.1460-9568.2004.03742.x.
The cortical representation of body parts is constantly modulated in response to the afferent input, and acute deafferentation of a body part results in bilateral cortical reorganization. To study the effects on hand function of right forearm anaesthesia, we investigated ten human subjects (group 1) for perception of touch, tactile discrimination and grip strength in the right (ipsilateral) and left (contralateral) hand before, during and 24 h after forearm skin anaesthesia with a local anaesthetic cream (EMLA). Ten age-matched controls (group 2) were investigated in the same way but received placebo. In group 1 a significant improvement was seen in tactile discrimination in the ipsilateral hand compared to base line (P = 0.009) and compared to group 2 (P = 0.006). The improvement in tactile discrimination remained for at least 24 h after anaesthesia. Perception of touch, was improved during anaesthesia compared to baseline values in group 1 (P = 0.046) and remained for at least 24 h. Grip strength did not change. These findings suggest that transient selective deafferentation of an extremity results in enhanced sensory functions of the functionally preserved parts of the same extremity, presumably as a result of expansion of adjacent cortical territories. Such rapid functional changes suggest unmasking of pre-existing synaptic connections as the mechanism underlying the acute modulation of sensory functions in the hand. Our findings open new perspectives for sensory re-education and rehabilitation following injury to the peripheral and central nervous system.
身体各部位的皮质表征会根据传入输入不断进行调节，身体某一部位的急性传入神经阻滞会导致双侧皮质重组。为了研究右前臂麻醉对手功能的影响，我们对10名人类受试者（第1组）在使用局部麻醉乳膏（复方利多卡因乳膏）进行前臂皮肤麻醉前、麻醉期间及麻醉后24小时，检测其右手（同侧）和左手（对侧）的触觉、触觉辨别能力和握力。以同样方式对10名年龄匹配的对照组（第2组）进行检测，但给予安慰剂。在第1组中，与基线相比（P = 0.009）以及与第2组相比（P = 0.006），同侧手的触觉辨别能力有显著改善。麻醉后，触觉辨别能力的改善至少持续24小时。与第1组的基线值相比，麻醉期间触觉有所改善（P = 0.046），且至少持续24小时。握力没有变化。这些发现表明，肢体的短暂选择性传入神经阻滞会导致同一肢体功能保留部分的感觉功能增强，这可能是相邻皮质区域扩大的结果。这种快速的功能变化表明，潜在的突触连接被揭示是手部感觉功能急性调节的潜在机制。我们的发现为周围和中枢神经系统损伤后的感觉再教育和康复开辟了新的前景。
