Spatial Pattern Coding of Sensory Information by Climbing Fiber-Evoked Calcium Signals in Networks of Neighboring Cerebellar Purkinje Cells
Spatial Pattern Coding of Sensory Information by Climbing Fiber-Evoked Calcium Signals in Networks of Neighboring Cerebellar Purkinje Cells
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DOI：
10.1523/jneurosci.4919-08.2009
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发表时间：
2009-06-24
影响因子：
5.3
通讯作者：
Haeusser, Michael
中科院分区：
文献类型：
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作者：
Schultz, Simon R.;Kitamura, Kazuo;Haeusser, Michael
攀爬纤维的输入在副矢状轴定向的小脑浦肯野细胞群中产生复杂的脉冲同步。阐明这种同步的精细空间结构对于理解其在橄榄小脑皮层回路中编码和处理感觉信息中的作用至关重要。我们利用体内多神经元双光子钙成像结合信息论分析对这些问题进行了研究。在多个相邻的浦肯野细胞中观察到与攀爬纤维输入相关的自发树突状钙瞬态。单个浦肯野细胞间钙瞬态的自发同步在大约200 μ m的中外侧下降，这与爬山纤维输入组织的小脑微区的存在一致。给药后同步性增强，与橄榄树起源一致。周期性的感觉刺激也会在刺激开始后导致同步性的短暂增加。为了研究同步如何影响复杂尖峰空间模式提供的神经种群编码，我们分析了其信息内容。我们发现，与不考虑空间起源的情况下计算整个池中的事件相比，来自小细胞群的钙事件的空间模式提供了更多的刺激信息（七个细胞群多59%）。信息理论分析表明，感官编码的相关效应主要由自发同步性所导致的冗余性所主导，而不是刺激依赖性对感觉编码的显著贡献。因此，橄榄小脑回路使用标记线代码来报告感觉信号，从而为同步在灵活选择输出到小脑深部核的信号中发挥了作用。
Climbing fiber input produces complex spike synchrony across populations of cerebellar Purkinje cells oriented in the parasagittal axis. Elucidating the fine spatial structure of this synchrony is crucial for understanding its role in the encoding and processing of sensory information within the olivocerebellar cortical circuit. We investigated these issues using in vivo multineuron two-photon calcium imaging in combination with information theoretic analysis. Spontaneous dendritic calcium transients linked to climbing fiber input were observed in multiple neighboring Purkinje cells. Spontaneous synchrony of calcium transients between individual Purkinje cells falls off over similar to 200 mu m mediolaterally, consistent with the presence of cerebellar microzones organized by climbing fiber input. Synchrony was increased after administration of harmaline, consistent with an olivary origin. Periodic sensory stimulation also resulted in a transient increase of synchrony after stimulus onset. To examine how synchrony affects the neural population code provided by the spatial pattern of complex spikes, we analyzed its information content. We found that spatial patterns of calcium events from small ensembles of cells provided substantially more stimulus information (59% more for seven-cell ensembles) than available by counting events across the pool without taking into account spatial origin. Information theoretic analysis indicated that, rather than contributing significantly to sensory coding via stimulus dependence, correlational effects on sensory coding are dominated by redundancy attributable to the prevalent spontaneous synchrony. The olivocerebellar circuit thus uses a labeled line code to report sensory signals, leaving open a role for synchrony in flexible selection of signals for output to deep cerebellar nuclei.