Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada;
Heart and Stroke Foundation, Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, Toronto, Ontario, Canada; and Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada.
J Neurophysiol. 2014 Jun 15;111(12):2634-43. doi: 10.1152/jn.00511.2013. Epub 2014 Mar 19.
The ability to correct balance disturbances is essential for the maintenance of upright stability. Although information about how the central nervous system controls balance reactions in humans remains limited, recent literature highlights a potentially important role for the cerebral cortex. The objective of this study was to determine the neural source of the well-reported balance-evoked N1 response. It was hypothesized that the N1 is associated with an "error-detection" event in response to the induced perturbation and therefore may be associated with activity within the anterior cingulate cortex (ACC). The localized source of the N1 evoked by perturbations to standing balance was compared, within each participant, to the location of an error-related negativity (ERN) known to occur within the ACC while performing a flanker task. In contrast to the main hypotheses, the results revealed that the location of the N1 was not within the ACC. The mean Talairach coordinates for the ERN were (6.47, -4.41, 41.17) mm, corresponding to the cingulate gyrus [Brodmann area (BA) 24], as expected. However, coordinates for the N1 dipole were (5.74, -11.81, 53.73) mm, corresponding to the medial frontal gyrus (BA 6), specifically the supplementary motor area. This may suggest the N1 is linked to the planning and execution of elements of the evoked balance reactions rather than being associated with error or event detection. Alternatively, it is possible that the N1 is associated with variation in the cortical representation due to task-specific differences in the activation of a distributed network of error-related processing. Subsequent work should focus on disentangling these two possible explanations as they relate to the cortical processing linked to reactive balance control.
纠正平衡障碍的能力对于维持直立稳定性至关重要。尽管有关中枢神经系统如何控制人类平衡反应的信息仍然有限，但最近的文献强调了大脑皮层的潜在重要作用。本研究的目的是确定众所周知的平衡诱发 N1 反应的神经源。假设 N1 与对诱导的扰动的“错误检测”事件相关，因此可能与前扣带皮层 (ACC) 内的活动相关。在每个参与者内，将平衡诱发的 N1 的局部源与在执行侧翼任务时已知发生在 ACC 内的与错误相关的负性 (ERN) 的位置进行比较。与主要假设相反，结果表明 N1 的位置不在 ACC 内。ERN 的平均 Talairach 坐标为 (6.47, -4.41, 41.17) mm，对应于扣带回 [Brodmann 区 (BA) 24]，如预期的那样。然而，N1 偶极子的坐标为 (5.74, -11.81, 53.73) mm，对应于额内侧回 (BA 6)，特别是辅助运动区。这可能表明 N1 与诱发平衡反应的元素的计划和执行有关，而不是与错误或事件检测有关。或者，N1 可能与由于与错误相关的处理的分布式网络的激活的特定任务差异而导致的皮质表示中的变化有关。后续工作应集中于厘清这两种可能的解释，因为它们与反应性平衡控制相关的皮质处理有关。
