Johansson Fredrik, Carlsson Hannes A E, Rasmussen Anders, Yeo Christopher H, Hesslow Germund
Associative Learning Group, Department of Experimental Medical Science, Lund University, 22184 Lund, Sweden; The Linnaeus Center Thinking in Time: Cognition, Communication & Learning, Lund University, 22184 Lund, Sweden.
Associative Learning Group, Department of Experimental Medical Science, Lund University, 22184 Lund, Sweden.
Cell Rep. 2015 Dec 1;13(9):1741-6. doi: 10.1016/j.celrep.2015.10.047. Epub 2015 Nov 19.
Cerebellar Purkinje cells can learn to respond to a conditioned stimulus with an adaptively timed pause in firing. This response was usually ascribed to long-term depression of parallel fiber to Purkinje cell synapses but has recently been shown to be due to a previously unknown form of learning involving an intrinsic cellular timing mechanism. Here, we investigate how these responses are elicited. They are resistant to blockade of GABAergic inhibition, suggesting that they are caused by glutamate release rather than by a changed balance between GABA and glutamate. We show that the responses are abolished by antagonists of the mGlu7 receptor but not significantly affected by other glutamate antagonists. These results support the existence of a distinct learning mechanism, different from changes in synaptic strength. They also demonstrate in vivo post-synaptic inhibition mediated by glutamate and show that the mGlu7 receptor is involved in activating intrinsic temporal memory.
小脑浦肯野细胞能够学会在受到条件刺激时，以适应性的定时放电暂停做出反应。这种反应通常被归因于平行纤维到浦肯野细胞突触的长时程抑制，但最近已表明它是由于一种以前未知的学习形式，涉及一种内在的细胞计时机制。在这里，我们研究这些反应是如何引发的。它们对GABA能抑制的阻断具有抗性，这表明它们是由谷氨酸释放引起的，而不是由GABA和谷氨酸之间平衡的改变引起的。我们表明，这些反应被mGlu7受体拮抗剂消除，但不受其他谷氨酸拮抗剂的显著影响。这些结果支持存在一种不同于突触强度变化的独特学习机制。它们还证明了由谷氨酸介导的体内突触后抑制，并表明mGlu7受体参与激活内在的时间记忆。
