Focal dystonia, by definition, affects a specific body part; however, it may have a widespread neural substrate. We tested this hypothesis by examining the intrinsic behaviour and the neuronal properties that are modulated by changes in the physiological behaviour of their connections, that is feedback dependence, of the isolated pallidal neurons. During deep brain stimulation surgery in 12 patients with isolated cervical dystonia (without hand involvement), we measured spontaneous as well as evoked single‐unit properties in response to fist making (hand movement) or shoulder shrug (neck movements). We measured the activity of isolated neurons that were only sensitive to the neck movements, hand movement, or not responsive to hand or neck movements. The spontaneous firing behaviour, such as the instantaneous firing rate and its regularity, was comparable in all three types of neurons. The neck movement‐sensitive neurons had prominent bursting behaviour in comparison with the hand neurons. The feedback dependence of the neck movement‐sensitive neurons was also significantly impaired when compared to hand movement‐sensitive neurons. Motor‐evoked change in firing rate of neck movement‐sensitive neurons rapidly declined; the decay time constant was much shorter compared to hand movement‐sensitive neurons. These results suggest that in isolated cervical dystonia, at the resolution of single neurons, the deficits are much widespread, affecting the neurons that drive the neck movement as well as the hand movements. We speculate that clinically discernable dystonia occurs when additional abnormality is added to baseline dysfunctional network, and one source of such abnormality may involve feedback.

中文翻译：

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依赖反馈的神经元特性使局灶性肌张力障碍变得如此局灶

顾名思义，局灶性肌张力障碍会影响特定的身体部位。然而，它可能具有广泛的神经底物。我们通过检查内在行为和神经元特性来检验这一假设，这些行为是由孤立的苍白神经元的连接的生理行为（即反馈依赖性）的变化所调节的。在对12例孤立性颈肌张力障碍（无手部受累）的患者进行深部脑刺激手术期间，我们测量了对拳头制造（手部运动）或耸肩（颈部运动）的自发性和诱发性单细胞特性。我们测量了仅对颈部运动，手部运动敏感或对手部或颈部运动无反应的孤立神经元的活动。自发放电行为，例如瞬时放电率及其规律性，在所有三种类型的神经元中均具有可比性。与手部神经元相比，对颈部运动敏感的神经元具有突出的爆发行为。与手部运动敏感神经元相比，颈部运动敏感神经元的反馈依赖性也显着降低。诱发运动的颈部运动敏感神经元放电速率迅速下降；与手部动作敏感神经元相比，衰减时间常数要短得多。这些结果表明，在孤立的颈肌张力障碍中，以单个神经元的分辨力，缺陷广泛分布，影响了驱动颈部运动和手部运动的神经元。我们推测，如果将其他异常添加到基线功能障碍网络中，就会发生临床上可辨别的肌张力障碍，