Department of Psychological & Brain Sciences, Indiana University Bloomington, 1101 E. 10th St., Bloomington, IN, 47405, USA.
Program in Neuroscience, Indiana University Bloomington, 1101 E. 10th St., Bloomington, IN, 47405, USA.
Cerebellum. 2020 Jun;19(3):383-391. doi: 10.1007/s12311-020-01114-w.
Delay eyeblink conditioning (dEBC) is widely used to assess cerebellar-dependent associative motor learning, including precise timing processes. Transcranial direct current stimulation (tDCS), noninvasive brain stimulation used to indirectly excite and inhibit select brain regions, may be a promising tool for understanding how functional integrity of the cerebellum influences dEBC behavior. The aim of this study was to assess whether tDCS-induced inhibition (cathodal) and excitation (anodal) of the cerebellum differentially impact timing of dEBC. A standard 10-block dEBC paradigm was administered to 102 healthy participants. Participants were randomized to stimulation conditions in a double-blind, between-subjects sham-controlled design. Participants received 20-min active (anodal or cathodal) stimulation at 1.5 mA (n = 20 anodal, n = 22 cathodal) or 2 mA (n = 19 anodal, n = 21 cathodal) or sham stimulation (n = 20) concurrently with dEBC training. Stimulation intensity and polarity effects on percent conditioned responses (CRs) and CR peak and onset latency were examined using repeated-measures analyses of variance. Acquisition of CRs increased over time at a similar rate across sham and all active stimulation groups. CR peak and onset latencies were later, i.e., closer to air puff onset, in all active stimulation groups compared to the sham group. Thus, tDCS facilitated cerebellar-dependent timing of dEBC, irrespective of stimulation intensity and polarity. These findings highlight the feasibility of using tDCS to modify cerebellar-dependent functions and provide further support for cerebellar contributions to human eyeblink conditioning and for exploring therapeutic tDCS interventions for cerebellar dysfunction.
延迟性眨眼条件反射（dEBC）被广泛用于评估小脑依赖性联想运动学习，包括精确的定时过程。经颅直流电刺激（tDCS）是一种非侵入性的大脑刺激方法，用于间接兴奋和抑制特定的大脑区域，可能是一种有前途的工具，可以了解小脑的功能完整性如何影响 dEBC 行为。本研究旨在评估小脑的 tDCS 诱导抑制（阴极）和兴奋（阳极）是否会对 dEBC 的定时产生不同的影响。使用标准的 10 块 dEBC 范式对 102 名健康参与者进行了测试。参与者在双盲、被试间 sham 对照设计中随机分配到刺激条件。参与者接受 20 分钟的 1.5 mA（n = 20 个阳极，n = 22 个阴极）或 2 mA（n = 19 个阳极，n = 21 个阴极）的活性（阳极或阴极）刺激或 sham 刺激（n = 20）与 dEBC 训练同时进行。使用重复测量方差分析检查刺激强度和极性对条件反应（CR）百分比、CR 峰值和起始潜伏期的影响。CRs 的获得随着时间的推移以相似的速度在 sham 和所有活性刺激组中增加。与 sham 组相比，所有活性刺激组的 CR 峰值和起始潜伏期都较晚，即更接近空气冲击的起始。因此，tDCS 促进了小脑依赖性 dEBC 的定时，而与刺激强度和极性无关。这些发现强调了使用 tDCS 来改变小脑依赖性功能的可行性，并进一步支持小脑对人类眨眼条件反射的贡献，并探索小脑功能障碍的治疗性 tDCS 干预。
