Functional connectivity between the thalamus and postsubiculum: analysis of evoked responses elicited by stimulation of the laterodorsal thalamic nucleus in anesthetized rats.
Functional connectivity between the thalamus and postsubiculum: analysis of evoked responses elicited by stimulation of the laterodorsal thalamic nucleus in anesthetized rats.
复制标题
丘脑和后下丘之间的功能连接：分析麻醉大鼠丘脑外侧核刺激引起的诱发反应。
DOI：
10.1002/hipo.22114
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发表时间：
2013
期刊：
影响因子：
3.5
通讯作者：
Shires KL
中科院分区：
文献类型：
--
作者：
Shires KL
丘脑背外侧核（LDN）提供了一个突出的传入投射到后下托（背侧前下托）。为了表征该通路中的突触传递，我们将刺激电极放置在LDN中，并记录在乌拉坦麻醉大鼠的后下托中引起的fEPSP。LDN刺激分别在后下托的深层和浅层之间引起源-汇偶极，这与丘脑传入在结构的浅层中终止的解剖学证据一致，并且存在具有延伸到这些层中的顶端树突的深层神经元。下丘脑后fEPSP的振幅通常为0.5-1.0 mV，峰值潜伏期约为6 ms。与解剖学观察结果一致，LDN刺激引起的fEPSP的短起始潜伏期及其跟随60-Hz刺激串的能力表明投射是单突触的。配对脉冲刺激显示出明显的配对脉冲抑制，在100 ms时最大，表明LDN-下托后突触的初始释放概率很高，这与许多新皮层通路相同。在海马通路中产生LTP的常规破伤风方案对下丘脑后fEPSP没有影响，但60 Hz刺激可诱导长期抑制。药物输注研究表明，LDN-下托后投射中的突触传递主要是AMPA-受体介导的。在大鼠后下托植入留置输液管，恢复期后，用乌拉坦麻醉，植入刺激电极和记录电极。CNQX的输注几乎完全消除了下丘脑后fEPSP，而D-AP 5几乎没有影响。然而，60-Hz LTD被D-AP 5输注阻断，表明这种形式的突触可塑性是NMDA受体依赖性的。© 2013威利期刊公司.
The laterodorsal nucleus (LDN) of the thalamus provides a prominent afferent projection to the postsubiculum (dorsal presubiculum). To characterize synaptic transmission in this pathway, we placed stimulating electrodes in the LDN and recorded fEPSPs elicited in the postsubiculum of urethane‐anesthetized rats. LDN stimulation elicited a source‐sink dipole between the deep and superficial layers of the postsubiculum, respectively, consistent with anatomical evidence for the termination of thalamic afferents in the superficial layers of the structure, and the existence of deep layer neurons with apical dendrites extending into these layers. Postsubicular fEPSPs were typically 0.5–1.0 mV in amplitude, with a peak latency of approximately 6 ms. Consistent with anatomical observations, the short onset latency of fEPSPs elicited by LDN stimulation, and their ability to follow a 60‐Hz train of stimulation, indicate that the projection is monosynaptic. Paired‐pulse stimulation revealed pronounced paired‐pulse depression that was maximal at 100 ms, suggesting that initial release probabilities are high at LDN‐postsubiculum synapses, in common with many neocortical pathways. A conventional tetanus protocol that yields LTP in hippocampal pathways had no effect on postsubicular fEPSPs, but long‐term depression could be induced by 60‐Hz stimulation. Drug infusion studies revealed that synaptic transmission in the LDN‐postsubiculum projection is predominantly AMPA‐receptor mediated. Rats were implanted with indwelling infusion cannulae targeting the postsubiculum, and, after a recovery period, were anaesthetized withurethane, and implanted with stimulating and recording electrodes. Infusion of CNQX almost completely abolished postsubicular fEPSPs, whereas D‐AP5 had little effect. However, 60‐Hz LTD was blocked by D‐AP5 infusion, revealing that this form of synaptic plasticity is NMDA‐receptor dependent. © 2013 Wiley Periodicals, Inc.