Multiple modes of network homeostasis in visual cortical layer 2/3
Multiple modes of network homeostasis in visual cortical layer 2/3
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DOI：
10.1523/jneurosci.5298-07.2008
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发表时间：
2008-04-01
影响因子：
5.3
通讯作者：
Turrigiano, Gina G.
中科院分区：
文献类型：
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作者：
Maffei, Arianna;Turrigiano, Gina G.
感觉经验对于发育过程中形成皮层微回路至关重要，并被认为通过几种形式的赫布和稳态可塑性来修改网络功能。这些不同形式的可塑性在皮层微回路中的特定突触类型中何时何地表达，以及它们如何相互作用，目前还知之甚少。在这里，我们研究了两种不同的视觉剥夺范式，眼睑缝合（LS）和眼内TTX，如何影响在经典的视觉系统可塑性的关键期内的大鼠视皮层2/3层的局部微电路。这两种形式的视觉剥夺产生了补偿性增加的自发放电的第2/3层锥体神经元在急性切片来自单眼视皮层。TTX通过增加2/3层内的兴奋/抑制（E/I）平衡来增加自发活动。相反，LS通过强烈抑制兴奋性传递来降低E/I平衡，并且通过增加2/3层锥体神经元的内在兴奋性来实现自发活动的稳态增加。因此，第2/3层中的微电路可以根据视觉体验产生的特定需求，使用不同形式的稳态可塑性来补偿视觉驱动的损失。多种、部分冗余形式的稳态可塑性的存在可以确保网络补偿能够响应广泛的感觉扰动。
Sensory experience is crucial for shaping the cortical microcircuit during development and is thought to modify network function through several forms of Hebbian and homeostatic plasticity. Where and when these different forms of plasticity are expressed at particular synapse types within cortical microcircuits, and how they interact, is poorly understood. Here we investigated how two different visual deprivation paradigms, lid suture (LS) and intraocular TTX, affect the local microcircuit within layer 2/3 of rat visual cortex during the classical critical period for visual system plasticity. Both forms of visual deprivation produced a compensatory increase in the spontaneous firing of layer 2/3 pyramidal neurons in acute slices derived from monocular visual cortex. TTX increased spontaneous activity through an increase in the excitation/ inhibition ( E/I) balance within layer 2/3. In contrast, LS decreased the E/I balance by strongly depressing excitatory transmission, and the homeostatic increase in spontaneous activity was instead achieved through an increase in the intrinsic excitability of layer 2/3 pyramidal neurons. The microcircuit in layer 2/3 can thus use different forms of homeostatic plasticity to compensate for the loss of visual drive, depending on the specific demands produced by visual experience. The existence of multiple, partially redundant forms of homeostatic plasticity may ensure that network compensation can be achieved in response to a wide range of sensory perturbations.