Computer Science, Chemnitz University of Technology, Straße der Nationen 62, Chemnitz, Germany.
Division of System Neurophysiology, National Institute for Physiological Sciences, Okazaki, Japan.
Eur J Neurosci. 2019 Mar;49(6):754-767. doi: 10.1111/ejn.13666. Epub 2017 Sep 10.
Theories and models of the basal ganglia have mainly focused on the role of three different corticothalamic pathways: direct, indirect and hyperdirect. Although the indirect and the hyperdirect pathways are linked through the bidirectional connections between the subthalamic nucleus (STN) and the external globus pallidus (GPe), the role of their interactions has been mainly discussed in the context of a dysfunction (abnormal oscillations in Parkinson's disease) and not of its function. We here propose a novel role for the loop formed by the STN and the GPe. We show, through a neuro-computational model, that this loop can bias the selection of actions during the exploratory period after a change in the environmental conditions towards alternative responses. Testing well-known alternative solutions before completely random actions can reduce the time required for the search of a new response after a rule change. Our simulations further show that the knowledge acquired by the indirect pathway can be transferred into a stable memory via learning in the hyperdirect pathway to establish the blocking of unwanted responses. After a rule switch, first the indirect pathway learns to inhibit the previously correct actions. Once the new correct association is learned, the inhibition is transferred to the hyperdirect pathway through synaptic plasticity.
直接通路、间接通路和超直接通路。虽然间接通路和超直接通路通过丘脑下核（STN）和外苍白球（GPe）之间的双向连接相互关联，但它们的相互作用主要是在功能障碍（帕金森病中的异常振荡）的背景下讨论的，而不是在其功能的背景下讨论的。我们在这里提出了 STN 和 GPe 形成的环路的一个新作用。我们通过一个神经计算模型表明，这个环路可以在环境条件变化后的探索期内，偏向于选择替代反应，从而对动作进行选择。在完全随机动作之前测试已知的替代解决方案，可以减少在规则改变后搜索新响应所需的时间。我们的模拟进一步表明，间接通路获得的知识可以通过超直接通路中的学习转移到稳定的记忆中，从而建立对不需要的反应的阻断。在规则切换后，间接通路首先学会抑制以前正确的动作。一旦新的正确关联被学习，抑制就通过突触可塑性转移到超直接通路。
