1 Cognitive-Motor Neuroscience Group and the Functional Neurosurgery Unit, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery, WC1N 3BG, UK.
Brain. 2014 May;137(Pt 5):1470-80. doi: 10.1093/brain/awu058. Epub 2014 Mar 22.
The aim of our study was to investigate two inter-related hypotheses about the role of the subthalamic nucleus. First that the subthalamic nucleus plays a role in adjusting response thresholds and speed-accuracy trade-offs and second that it is involved in reactive and proactive inhibition and conflict resolution. These were addressed by comparing the performance of 10 patients with Parkinson's disease treated with right subthalamotomy and 12 patients with left subthalamotomy, to 14 unoperated patients with Parkinson's disease and 23 age-matched healthy control participants on a conditional stop signal task and applying the drift diffusion model. Unilateral subthalamotomy significantly improved Parkinson's disease motor signs. Patients with right subthalamotomy had significantly faster Go reaction times with their contra-lesional hand than the unoperated patients and did not differ from the control participants, indicating their speed of response initiation was 'normalized'. However, operated patients made significantly more discrimination errors than unoperated patients and controls, suggesting that subthalamotomy influenced speed-accuracy trade-offs. This was confirmed by the drift diffusion model, revealing that while the unoperated patients had significantly lower drift rate and higher response thresholds than the control participants, the response thresholds for the operated groups did not differ from the controls and the patients with right subthalamotomy had a significantly higher drift rate than unoperated patients and similar to that of controls. The drift diffusion model further established that unlike the control participants, operated patients failed to show context-dependent strategic modulation of response thresholds. The patients with right subthalamotomy could not engage in late phase, fast inhibition of the response and showed minimal proactive inhibition when tested with the contra-lesional hand. These results provide strong evidence that the subthalamic nucleus is involved in response inhibition, in modulating the rate of information accumulation and the response threshold and influencing the balance between speed and accuracy of performance. Accordingly, the subthalamic nucleus can be considered a key component of the cerebral inhibitory network.
我们研究的目的是探讨关于底丘脑核作用的两个相互关联的假设。首先，底丘脑核在调整反应阈值和速度-准确性权衡方面发挥作用；其次，它参与了反应性和前摄性抑制以及冲突解决。通过比较 10 例接受右侧底丘脑切开术治疗的帕金森病患者、12 例接受左侧底丘脑切开术治疗的患者与 14 例未手术的帕金森病患者和 23 名年龄匹配的健康对照参与者在条件停止信号任务上的表现，并应用漂移扩散模型来解决这些问题。单侧底丘脑切开术显著改善了帕金森病的运动症状。右侧底丘脑切开术的患者与未手术患者相比，其对侧手的 Go 反应时间明显更快，且与对照组参与者无差异，表明他们的反应起始速度“正常化”。然而，手术患者的辨别错误明显多于未手术患者和对照组参与者，表明底丘脑切开术影响了速度-准确性权衡。这一结果通过漂移扩散模型得到了证实，该模型显示，与对照组参与者相比，未手术患者的漂移率显著降低，反应阈值显著升高，而手术组的反应阈值与对照组无差异，且右侧底丘脑切开术患者的漂移率显著高于未手术患者，与对照组相似。漂移扩散模型进一步证实，与对照组参与者不同，手术患者未能表现出对反应阈值的上下文相关策略性调节。右侧底丘脑切开术患者无法进行后期快速的反应抑制，并且在用对侧手进行测试时，表现出最小的前摄性抑制。这些结果提供了强有力的证据表明，底丘脑核参与了反应抑制，调节了信息积累的速度和反应阈值，并影响了速度和准确性表现之间的平衡。因此，可以认为底丘脑核是大脑抑制网络的关键组成部分。
