Thalamocortical long-term potentiation becomes gated after the early critical period in the auditory cortex.
Thalamocortical long-term potentiation becomes gated after the early critical period in the auditory cortex.
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DOI：
10.1523/jneurosci.4500-12.2013
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发表时间：
2013-04-24
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影响因子：
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通讯作者：
Zakharenko SS
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文献类型：
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作者：
Chun S;Bayazitov IT;Blundon JA;Zakharenko SS
感觉皮层中的皮层地图是可塑性的，会随着感觉体验的变化而变化。这种可塑性的细胞部位目前还存在争议。丘脑皮质（TC）投射将感觉信息传递到感觉皮质。TC突触目前被认为是皮质地图可塑性的一个位点，因为TC突触可塑性被认为是有限的新生儿，而皮质地图可塑性可以在新生儿和成人中诱导。然而，在成年人的听觉皮层（ACx），皮质地图可塑性可以诱导，如果动物参加一个声音或接收的声音与激活的胆碱能输入从基底核配对。我们现在表明，在ACx，长时程增强（LTP），突触可塑性的一种主要形式，表达在TC突触在年轻和成熟的小鼠，但成为门控随着年龄的增长。使用单细胞电生理学，双光子谷氨酸释放，和光遗传学在丘脑皮层切片含有听觉丘脑和ACx，我们表明，TC LTP表达突触后，并依赖于第一组代谢型谷氨酸受体。成熟ACx的TC LTP可以通过皮层去抑制结合基底核胆碱能输入的激活来揭示。通过丘脑辐射传递的胆碱能输入激活TC投射上的M1毒蕈碱受体，并通过A1腺苷受体对突触前腺苷信号传导的负调节维持TC突触处的谷氨酸释放。这些数据表明，TC LTP在ACx持续整个生命，因此可能有助于经验依赖性皮质地图可塑性的ACx在年轻人和成年人。
Cortical maps in sensory cortices are plastic, changing in response to sensory experience. The cellular site of such plasticity is currently debated. Thalamocortical (TC) projections deliver sensory information to sensory cortices. TC synapses are currently dismissed as a locus of cortical map plasticity because TC synaptic plasticity is thought to be limited to neonates, whereas cortical map plasticity can be induced in both neonates and adults. However, in the auditory cortex (ACx) of adults, cortical map plasticity can be induced if animals attend to a sound or receive sounds paired with activation of cholinergic inputs from the nucleus basalis. We now show that in the ACx, long-term potentiation (LTP), a major form of synaptic plasticity, is expressed at TC synapses in both young and mature mice but becomes gated with age. Using single-cell electrophysiology, two-photon glutamate uncaging, and optogenetics in thalamocortical slices containing the auditory thalamus and ACx, we show that TC LTP is expressed postsynaptically and depends on group I metabotropic glutamate receptors. TC LTP in mature ACx can be unmasked by cortical disinhibition combined with activation of cholinergic inputs from the nucleus basalis. Cholinergic inputs passing through the thalamic radiation activate M1 muscarinic receptors on TC projections and sustain glutamate release at TC synapses via negative regulation of presynaptic adenosine signaling through A1 adenosine receptors. These data indicate that TC LTP in the ACx persists throughout life and therefore can potentially contribute to experience-dependent cortical map plasticity in the ACx in both young and adults.