Connectivity patterns revealed by mapping of active inputs on dendrites of thalamorecipient neurons in the auditory cortex.
Connectivity patterns revealed by mapping of active inputs on dendrites of thalamorecipient neurons in the auditory cortex.
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DOI：
10.1523/jneurosci.0258-09.2009
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发表时间：
2009-05-20
期刊：
影响因子：
--
通讯作者：
Zakharenko SS
中科院分区：
文献类型：
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作者：
Richardson RJ;Blundon JA;Bayazitov IT;Zakharenko SS
尽管在数量上远远超过丘脑受体神经元的皮质内输入，但丘脑皮质投射有效地将声学信息传递给听觉皮层。我们假设丘脑投射可能通过在皮层神经元树突树的最佳位置形成突触来实现有效性。利用树突棘双光子钙成像技术，我们在小鼠丘脑皮层切片的丘脑受体皮质神经元树突树上构建了活跃的丘脑和皮质内输入图。这些图谱显示，丘脑投射突触优先发生在距体细胞100 μm以内的粗短树突棘上，而接受皮层内投射的棘的位置和形态则具有不太明确的模式。利用笼状谷氨酸双光子光解实验，我们发现，与远端树突棘或其他形态类型的棘相比，位于体周的短突树突棘的激活在丘脑受体神经元体细胞中产生更大的突触后电位。这些结果提示了丘脑投射可靠性的一种新机制——关键传入输入在最佳突触位置的定位。
Despite being substantially outnumbered by intracortical inputs on thalamorecipient neurons, thalamocortical projections efficiently deliver acoustic information to the auditory cortex. We hypothesized that thalamic projections may achieve effectiveness by forming synapses at optimal locations on dendritic trees of cortical neurons. Using two-photon calcium imaging in dendritic spines, we constructed maps of active thalamic and intracortical inputs on dendritic trees of thalamorecipient cortical neurons in mouse thalamocortical slices. These maps revealed that thalamic projections synapse preferentially on stubby dendritic spines within 100 μm of the soma, whereas the locations and morphology of spines that receive intracortical projections have a less-defined pattern. Using two-photon photolysis of caged glutamate we found that activation of stubby dendritic spines located perisomatically generated larger postsynaptic potentials in the soma of thalamorecipient neurons than did activation of remote dendritic spines or spines of other morphological types. These results suggest a novel mechanism of reliability of thalamic projections —the positioning of crucial afferent inputs at optimal synaptic locations.