Nature:經驗怎樣調製神經可塑性

大腦能夠學習和存儲記憶的能力與可塑性、即神經通道和突觸響應於行為、環境和其他輸入而發生變化的能力有關。在生命早期關鍵時期的可塑性以前被與「表達小清蛋白的中間神經元」 (PV+ 細胞)的成熟相聯繫，但我們對其中發揮作用的機制卻知之甚少。

在這項研究中，Pico Caroni及同事識別出了與成年小鼠的中間神經元中的小清蛋白表達水平相關的不同網絡狀態。環境強化促使PV表達水平低的細胞增加，而害怕狀態會造成PV表達水平高的細胞增加。每個狀態都有表現出會影響該網絡的不同生理特性的細胞。簡單地人工激發或抑制這些細胞，就足以改變這種狀態以及決定該狀態的結構可塑性。

這些結果表明，存在著一個與學習相關的可塑性機制，它依賴於PV+ 細胞的構形和狀態；該機制也許可被用於治療方案，來促進認知增強和神經保護。（生物谷Bioon.com）

生物谷推薦的英文摘要

Nature                    doi:10.1038/nature12866

Parvalbumin-expressing basket-cell network plasticity induced by experience regulates adult learning

Flavio Donato，Santiago Belluco Rompani& Pico Caroni

Learning and memory processes can be influenced by recent experience， but the mechanisms involved are poorly understood. Enhanced plasticity during critical periods of early life is linked to differentiating parvalbumin (PV)-interneuron networks1， 2， 3， 4， 5， 6， 7， suggesting that recent experience may modulate learning by targeting the differentiation state of PV neurons8， 9， 10， 11 in the adult. Here we show that environmental enrichment and Pavlovian contextual fear conditioning induce opposite， sustained and reversible hippocampal PV-network configurations in adult mice. Specifically， enrichment promotes the emergence of large fractions of low-differentiation (low PV and GAD67 expression) basket cells with low excitatory-to-inhibitory synaptic-density ratios， whereas fear conditioning leads to large fractions of high-differentiation (high PV and GAD67 expression) basket cells with high excitatory-to-inhibitory synaptic-density ratios. Pharmacogenetic inhibition or activation of PV neurons was sufficient to induce such opposite low-PV-network or high-PV-network configurations， respectively. The low-PV-network configuration enhanced structural synaptic plasticity12， 13， and memory consolidation and retrieval， whereas these were reduced by the high-PV-network configuration. We then show that maze navigation learning14 induces a hippocampal low-PV-network configuration paralleled by enhanced memory and structural synaptic plasticity throughout training， followed by a shift to a high-PV-network configuration after learning completion. The shift to a low-PV-network configuration specifically involved increased vasoactive intestinal polypeptide (VIP)-positive GABAergic boutons and synaptic transmission onto PV neurons15， 16. Closely comparable low- and high-PV-network configurations involving VIP boutons were specifically induced in primary motor cortex upon rotarod motor learning17， 18. These results uncover a network plasticity mechanism induced after learning through VIP–PV microcircuit modulation19， and involving large， sustained and reversible shifts in the configuration of PV basket-cell networks in the adult. This novel form of experience-related plasticity in the adult modulates memory consolidation， retrieval and learning， and might be harnessed for therapeutic strategies to promote cognitive enhancement and neuroprotection.