Department of Neurology, University of Duisburg-Essen, Hufelandstrasse 55, 45147, Essen, Germany.
Department of Neurology, Johns Hopkins University, Baltimore, MD, USA.
Cerebellum. 2019 Feb;18(1):67-75. doi: 10.1007/s12311-018-0956-z.
The cerebellum and the prefrontal cortex are assumed to play a role in the pathophysiology of essential tremor (ET). Trace eyeblink conditioning with a long interstimulus interval relies on an intact function of the hippocampus, prefrontal cortex (PFC), and, although marginally, of the cerebellum. The aim of the present study was to evaluate whether long trace eyeblink conditioning is impaired in patients with ET. In 18 patients with ET and 18 controls, a long trace conditioning paradigm was applied. Following 100 paired conditioned response-unconditioned response trials, 30 conditioned response alone trials were given as extinction trials. The degree of tremor and the presence of accompanying cerebellar signs were determined based on clinical scales. The acquisition of conditioned eyeblink responses was not impaired in the group of all patients compared to controls (mean total incidences of conditioned responses in patients 23.3 ± 14.5%, in controls 24.1 ± 13.9%; P = 0.88). In the subgroup of six patients with cerebellar signs, incidences of conditioned responses were numerically but not significantly lower (16.4 ± 9.9%) compared to patients without cerebellar signs (26.8 ± 15.5%; P = 0.16). Trace eyeblink conditioning with a long interstimulus interval was not impaired in subjects with ET. Patients with clinical cerebellar signs presented slightly reduced conditioning. Areas of the PFC contributing to trace eyeblink conditioning appear less affected in ET. Future studies also using a shorter trace interval should include a larger group of subjects in all stages of ET.
小脑和前额叶皮层被认为在特发性震颤（ET）的病理生理学中起作用。长间隔的瞬目条件反射依赖于海马、前额叶皮层（PFC）的完整功能，尽管小脑的作用略有边缘。本研究旨在评估长轨迹瞬目条件反射是否在 ET 患者中受损。在 18 名 ET 患者和 18 名对照组中，应用了长轨迹条件反射范式。在 100 对条件反射-非条件反射试验后，给予 30 次单独条件反射试验作为消退试验。根据临床量表确定震颤程度和伴随的小脑体征的存在。与对照组相比，所有患者组的条件性眨眼反应的获得均未受损（患者的条件性反应总发生率为 23.3±14.5%，对照组为 24.1±13.9%；P=0.88）。在有小脑体征的 6 名患者亚组中，条件性反应的发生率虽略有但无统计学意义降低（16.4±9.9%）与无小脑体征的患者相比（26.8±15.5%；P=0.16）。长间隔瞬目条件反射在 ET 患者中并未受损。有临床小脑体征的患者的条件反射稍差。参与长轨迹瞬目条件反射的 PFC 区域在 ET 中似乎受影响较小。未来的研究也应包括所有 ET 阶段的更大样本量，还应使用更短的间隔时间。
