Mogensen Hannes, Bengtsson Fredrik, Jörntell Henrik
Neural Basis of Sensorimotor Control, Department of Experimental Medical Science, Lund University, BMC F10, Tornavägen 10, 221 84, Lund, Sweden.
Cerebellum. 2017 Jun;16(3):638-647. doi: 10.1007/s12311-016-0839-0.
The existence of input plasticity in the deep cerebellar nuclear (DCN) cells of the adult cerebellum could have profound implications for our understanding of cerebellar function. Whereas the existence of plastic changes in mossy fiber (mf) synaptic responses in DCN neurons has been demonstrated in juvenile slices, there has so far been no direct demonstration of this form of plasticity in the adult cerebellum in vivo. In the present paper, we recorded from neurons in the anterior interposed nucleus (AIN) and stimulated the spinocerebellar tracts (SCT) directly or via the skin to obtain mf activation and the inferior olive to activate climbing fibers (cfs) in the nonanesthetized, adult, decerebrated cat. We used three different types of protocols that theoretically could be expected to induce plasticity, each of which involved episodically intense afferent activation lasting for 10 min. These were conjunctive mf-cf activation, which effectively induces plasticity in cortical neurons; mf and cf activation in a pattern resembling the protocol for inducing classical conditioning; and conjunctive activation of two excitatory mf inputs. None of these protocols had any statistically significant effect on the evoked responses in the AIN neurons. We conclude that the input plasticity for excitatory mfs in the AIN cells of the adult cerebellum in vivo is likely to be less effective than that of parallel fiber synaptic inputs in cerebellar cortical cells, at least in the timespan of 1 h.
成年小脑深部小脑核（DCN）细胞中输入可塑性的存在，可能对我们理解小脑功能具有深远意义。虽然在幼年切片中已证明DCN神经元中苔藓纤维（mf）突触反应存在可塑性变化，但迄今为止，在成年小脑的体内尚未直接证明这种可塑性形式。在本文中，我们在未麻醉的成年去脑猫中，记录前间位核（AIN）神经元的活动，并直接或通过皮肤刺激脊髓小脑束（SCT）以获得mf激活，刺激下橄榄核以激活攀缘纤维（cf）。我们使用了三种理论上有望诱导可塑性的不同类型的方案，每种方案都涉及持续10分钟的间歇性强烈传入激活。这些方案分别是联合mf-cf激活（可有效诱导皮质神经元的可塑性）、以类似于诱导经典条件反射的方案模式进行的mf和cf激活，以及两个兴奋性mf输入的联合激活。这些方案均未对AIN神经元的诱发反应产生任何统计学上的显著影响。我们得出结论，至少在1小时的时间范围内，成年小脑体内AIN细胞中兴奋性mf的输入可塑性可能比小脑皮质细胞中平行纤维突触输入的可塑性效果更差。
