Milshtein-Parush Hila, Frere Samuel, Regev Limor, Lahav Coren, Benbenishty Amit, Ben-Eliyahu Shamgar, Goshen Inbal, Slutsky Inna
Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel.
Cereb Cortex. 2017 Jun 1;27(6):3457-3470. doi: 10.1093/cercor/bhx084.
Hippocampus, a temporal lobe structure involved in learning and memory, receives information from all sensory modalities. Despite extensive research on the role of sensory experience in cortical map plasticity, little is known about whether and how sensory experience regulates functioning of the hippocampal circuits. Here, we show that 9 ± 2 days of whisker deprivation during early mouse development depresses activity of CA3 pyramidal neurons by several principal mechanisms: decrease in release probability, increase in the fraction of silent synapses, and reduction in intrinsic excitability. As a result of deprivation-induced presynaptic inhibition, CA3-CA1 synaptic facilitation was augmented at high frequencies, shifting filtering properties of synapses. The changes in the AMPA-mediated synaptic transmission were accompanied by an increase in NR2B-containing NMDA receptors and a reduction in the AMPA/NMDA ratio. The observed reconfiguration of the CA3-CA1 connections may represent a homeostatic adaptation to augmentation in synaptic activity during the initial deprivation phase. In adult mice, tactile disuse diminished intrinsic excitability without altering synaptic facilitation. We suggest that sensory experience regulates computations performed by the hippocampus by tuning its synaptic and intrinsic characteristics.
海马体是一个参与学习和记忆的颞叶结构,它接收来自所有感觉模态的信息。尽管对感觉经验在皮质图谱可塑性中的作用进行了广泛研究,但对于感觉经验是否以及如何调节海马回路的功能却知之甚少。在这里,我们表明,在小鼠早期发育过程中9±2天的触须剥夺通过几种主要机制抑制了CA3锥体神经元的活动:释放概率降低、沉默突触比例增加以及内在兴奋性降低。由于剥夺诱导的突触前抑制,CA3-CA1突触易化在高频时增强,改变了突触的滤波特性。AMPA介导的突触传递变化伴随着含NR2B的NMDA受体增加以及AMPA/NMDA比值降低。观察到的CA3-CA1连接的重新配置可能代表了对初始剥夺阶段突触活动增强的一种稳态适应。在成年小鼠中,触觉废用减少了内在兴奋性,但没有改变突触易化。我们认为,感觉经验通过调节海马体的突触和内在特性来调控其执行的计算。