Division of Neuropsychology, Institute of Psychology, and International Normal Aging and Plasticity Imaging Center, University of Zurich, Zurich, Switzerland.
Neurology. 2012 Jan 17;78(3):182-8. doi: 10.1212/WNL.0b013e31823fcd9c.
Little is known about the effects of reduced sensory input and motor output in the human brain. Therefore, we conducted a longitudinal study to investigate whether limb immobilization after unilateral arm injury is reflected in structural plastic changes in gray matter (cortical thickness) and white matter (fractional anisotropy [FA]).
We examined 10 right-handed subjects with injury of the right upper extremity that required at least 14 days of limb immobilization. Subjects underwent 2 MRI examinations, the first within 48 hours postinjury and the second after an average time interval of 16 days of immobilization. Based on the MRI scans, we measured cortical thickness of sensorimotor regions and FA of the corticospinal tracts.
After immobilization, we revealed a decrease in cortical thickness in the left primary motor and somatosensory area as well as a decrease in FA in the left corticospinal tract. In addition, the motor skill of the left (noninjured) hand improved and is related to increased cortical thickness and FA in the right motor cortex.
The present study illustrates that cortical thickness of the sensorimotor cortex and FA of the corticospinal tract changed during right arm immobilization and that these changes are associated with skill transfer from the right to the left hand. Thus, immobilization induces rapid reorganization of the sensorimotor system. Given that limb immobilization is a standard intervention technique in constraint-induced therapy, therapists should be aware of both the positive and negative effects of this intervention.
人类大脑中感觉输入和运动输出减少的影响知之甚少。因此，我们进行了一项纵向研究，以调查单侧上肢损伤后肢体固定是否反映在灰质（皮质厚度）和白质（各向异性分数 [FA]）的结构塑性变化中。
我们检查了 10 名右利手受试者，他们的右上肢受伤需要至少 14 天的肢体固定。受试者接受了 2 次 MRI 检查，第一次在受伤后 48 小时内进行，第二次在固定后平均 16 天进行。根据 MRI 扫描，我们测量了感觉运动区域的皮质厚度和皮质脊髓束的 FA。
固定后，我们发现左侧初级运动和体感区的皮质厚度降低，左侧皮质脊髓束的 FA 降低。此外，左手（未受伤）的运动技能提高，与右侧运动皮层的皮质厚度和 FA 增加有关。
本研究表明，右臂固定期间感觉运动皮层的皮质厚度和皮质脊髓束的 FA 发生变化，这些变化与从右手到左手的技能转移有关。因此，固定会导致感觉运动系统的快速重组。鉴于肢体固定是强制性诱导治疗中的一种标准干预技术，治疗师应该意识到这种干预的积极和消极影响。
