Synaptic cooperativity regulates persistent network activity in neocortex.
Synaptic cooperativity regulates persistent network activity in neocortex.
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DOI：
10.1523/jneurosci.4424-12.2013
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发表时间：
2013-02-13
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影响因子：
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通讯作者：
Castro-Alamancos MA
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作者：
Favero M;Castro-Alamancos MA
在行为静止期间，新大脑皮层产生自发的缓慢振荡，可能包括向上和向下状态。向上状态是持续活动的短暂时期，类似于在觉醒和认知过程中激活的新皮质。新皮质通路中的神经活动可以触发状态，但控制状态发生的变量却知之甚少。我们使用成年小鼠的丘脑皮质切片来探索丘脑皮质和皮质内突触的协同性(重合传入神经元的数量)在推动状态上升中的作用。在表达视紫红质-2的通路中，通过改变电刺激或蓝光刺激的强度来调节协作性。我们发现，光遗传学极大地改进了切片中丘脑皮质通路的研究，因为它产生的丘脑皮质反应类似于在体内观察到的反应。结果表明，由丘脑皮质或皮质内快速AMPA受体兴奋引起的突触协同性越强，对UP状态的抑制就越强，因为它驱动了更强的前馈抑制。相反，在抑制UP状态的强突触协同作用中，阻止快速兴奋，从而导致其驱动的前馈抑制，揭开了完全由缓慢的NMDA受体兴奋介导的状态。无论通路的起源如何，由快速兴奋介导的协同性与兴奋性突触通路在新皮质中触发状态的能力成反比。
During behavioral quiescence, the neocortex generates spontaneous slow oscillations, which may consist of Up and Down states. Up states are short epochs of persistent activity that resemble the activated neocortex during arousal and cognition. Neural activity in neocortical pathways can trigger Up states but the variables that control their occurrence are poorly understood. We used thalamocortical slices from adult mice to explore the role of thalamocortical and intracortical synaptic cooperativity (the number of coincident afferents) in driving Up states. Cooperativity was adjusted by varying the intensity of electrical or blue light stimuli in pathways that express channelrhodopsin-2. We found that optogenetics greatly improves the study of thalamocortical pathways in slices because it produces thalamocortical responses that resemble those observed in vivo. The results indicate that more synaptic cooperativity, caused by either thalamocortical or intracortical fast AMPA receptor excitation, leads to more robust inhibition of Up states because it drives stronger feed-forward inhibition. Conversely, during strong synaptic cooperativity that suppresses Up states, blocking fast excitation, and as a result the feed-forward inhibition it drives, unmasks Up states that are entirely mediated by slow NMDA receptor excitation. Regardless of the pathway’s origin, cooperativity mediated by fast excitation is inversely related to the ability of excitatory synaptic pathways to trigger Up states in neocortex.