Brain Health Research Centre and Brain Research NZ Centre of Research Excellence, Department of Anatomy, University of Otago, New Zealand.
Brain Health Research Centre and Brain Research NZ Centre of Research Excellence, Department of Anatomy, University of Otago, New Zealand.
Brain Stimul. 2017 Mar-Apr;10(2):214-222. doi: 10.1016/j.brs.2017.01.006. Epub 2017 Jan 11.
BACKGROUND/OBJECTIVES: Interhemispheric inhibition in the brain plays a dynamic role in the production of voluntary unimanual actions. In stroke, the interhemispheric imbalance model predicts the presence of asymmetry in interhemispheric inhibition, with excessive inhibition from the contralesional hemisphere limiting maximal recovery. Stimulation methods to reduce this asymmetry in the brain may be promising as a stroke therapy, however determining how to best measure and modulate interhemispheric inhibition and who is likely to benefit, remain important questions.
This review addresses current understanding of interhemispheric inhibition in the healthy and stroke lesioned brain. We present a review of studies that have measured interhemispheric inhibition using different paradigms in the clinic, as well as results from recent animal studies investigating stimulation methods to target abnormal inhibition after stroke.
MAIN FINDINGS/DISCUSSION: The degree to which asymmetric interhemispheric inhibition impacts on stroke recovery is controversial, and we consider sources of variation between studies which may contribute to this debate. We suggest that interhemispheric inhibition is not static following stroke in terms of the movement phase in which it is aberrantly engaged. Instead it may be dynamically increased onto perilesional areas during early movement, thus impairing motor initiation. Hence, its effect on stroke recovery may differ between studies depending on the technique and movement phase of eliciting the measurement. Finally, we propose how modulating excitability in the brain through more specific targeting of neural elements underlying interhemispheric inhibition via stimulation type, location and intensity may raise the ceiling of recovery following stroke and enhance functional return.
背景/目的：大脑中的半球间抑制在自愿单侧运动的产生中起着动态作用。在中风中，半球间不平衡模型预测了半球间抑制的不对称性的存在，来自对侧半球的过度抑制限制了最大恢复。减少大脑中这种不对称性的刺激方法可能是一种有前途的中风治疗方法，但如何最好地测量和调节半球间抑制以及谁可能受益，仍然是重要的问题。
本综述讨论了健康和中风受损大脑中半球间抑制的当前理解。我们介绍了使用不同范式在临床中测量半球间抑制的研究，并介绍了最近研究动物刺激方法以针对中风后异常抑制的研究结果。
主要发现/讨论：不对称半球间抑制对中风恢复的影响程度存在争议，我们考虑了导致这一争论的研究之间的变异来源。我们认为，从运动阶段来看，中风后半球间抑制并不是静态的。相反，它可能在早期运动期间动态地增加到病变周围区域，从而损害运动起始。因此，它对中风恢复的影响可能因研究而异，具体取决于激发测量的技术和运动阶段。最后，我们提出如何通过更具体地针对刺激类型、位置和强度来调节大脑中的兴奋性，从而提高中风后的恢复上限并增强功能恢复。
