Pope Paul A, Miall R Chris
School of Psychology, University of Birmingham , Birmingham , UK.
Front Psychiatry. 2014 Apr 2;5:33. doi: 10.3389/fpsyt.2014.00033. eCollection 2014.
Numerous studies have highlighted the possibility of modulating the excitability of cerebro-cerebellar circuits bi-directionally using transcranial electrical brain stimulation, in a manner akin to that observed using magnetic stimulation protocols. It has been proposed that cerebellar stimulation activates Purkinje cells in the cerebellar cortex, leading to inhibition of the dentate nucleus, which exerts a tonic facilitatory drive onto motor and cognitive regions of cortex through a synaptic relay in the ventral-lateral thalamus. Some cerebellar deficits present with cognitive impairments if damage to non-motor regions of the cerebellum disrupts the coupling with cerebral cortical areas for thinking and reasoning. Indeed, white matter changes in the dentato-rubral tract correlate with cognitive assessments in patients with Friedreich ataxia, suggesting that this pathway is one component of the anatomical substrate supporting a cerebellar contribution to cognition. An understanding of the physiology of the cerebro-cerebellar pathway previously helped us to constrain our interpretation of results from two recent studies in which we showed cognitive enhancements in healthy participants during tests of arithmetic after electrical stimulation of the cerebellum, but only when task demands were high. Others studies have also shown how excitation of the prefrontal cortex can enhance performance in a variety of working memory tasks. Thus, future efforts might be guided toward neuro-enhancement in certain patient populations, using what is commonly termed "non-invasive brain stimulation" as a cognitive rehabilitation tool to modulate cerebro-cerebellar circuits, or for stimulation over the cerebral cortex to compensate for decreased cerebellar drive to this region. This article will address these possibilities with a review of the relevant literature covering ataxias and cerebellar cognitive affective disorders, which are characterized by thalamo-cortical disturbances.
众多研究强调了使用经颅电刺激双向调节脑-小脑回路兴奋性的可能性，其方式类似于使用磁刺激方案所观察到的那样。有人提出，小脑刺激会激活小脑皮质中的浦肯野细胞，导致齿状核受到抑制，而齿状核通过腹外侧丘脑的突触中继，对皮质的运动和认知区域施加持续性的促进驱动。如果小脑非运动区域的损伤破坏了与大脑皮质区域在思维和推理方面的耦合，一些小脑缺陷就会伴有认知障碍。事实上，弗里德赖希共济失调患者的齿状红核束白质变化与认知评估相关，这表明该通路是支持小脑对认知有贡献的解剖学基础的一个组成部分。对脑-小脑通路生理学的理解此前帮助我们对两项近期研究的结果进行解读，在这两项研究中，我们发现对小脑进行电刺激后，健康参与者在算术测试期间的认知能力有所增强，但仅在任务要求较高时才会如此。其他研究也表明前额叶皮质的兴奋如何能提高各种工作记忆任务的表现。因此，未来的努力可能会朝着对某些患者群体进行神经增强的方向发展，使用通常所说的“非侵入性脑刺激”作为一种认知康复工具来调节脑-小脑回路，或者对大脑皮质进行刺激，以补偿该区域小脑驱动的减少。本文将通过回顾有关共济失调和小脑认知情感障碍的相关文献来探讨这些可能性，这些疾病的特征是丘脑-皮质功能紊乱。
