Patients suffering from temporal lobe epilepsy (TLE) show severe problems in hippocampus dependent memory consolidation. Memory consolidation strongly depends on an intact dialog between the hippocampus and neocortical structures. Deficits in hippocampal signal transmission are known to provoke disturbances in memory formation. In the present study, we investigate changes of synaptic plasticity at hippocampal output structures in an experimental animal model of TLE. In pilocarpine-treated rats, we found suppressed long-term potentiation (LTP) in hippocampal and parahippocampal regions such as the subiculum and the entorhinal cortex (EC). Subsequently we focused on the subiculum, serving as the major relay station between the hippocampus proper and downstream structures. In control animals, subicular pyramidal cells express different forms of LTP depending on their intrinsic firing pattern. In line with our extracellular recordings, we could show that LTP could only be induced in a minority of subicular pyramidal neurons. We demonstrate that a well-characterized cAMP-dependent signaling pathway involved in presynaptic forms of LTP is perturbed in pilocarpine-treated animals. Our findings suggest that in TLE, disturbances of synaptic plasticity may influence the information flow between the hippocampus and the neocortex.

患有颞叶癫痫（TLE）的患者在海马依赖性记忆巩固中表现出严重问题。记忆巩固在很大程度上取决于海马体与新皮质结构之间的完整对话。已知海马信号传输的不足会引起记忆形成障碍。在本研究中，我们调查了TLE实验动物模型中海马输出结构突触可塑性的变化。在毛果芸香碱治疗的大鼠中，我们发现海马和海马旁区域（例如下丘脑和内嗅皮层（EC））的长期增强作用（LTP）受抑制。随后，我们将重点放在下颌，作为海马固有结构和下游结构之间的主要中继站。在对照动物中 特定的锥体细胞根据其固有的发射模式表达不同形式的LTP。与我们的细胞外记录一致，我们可以证明LTP只能在少数亚类锥体神经元中被诱导。我们证明在毛果芸香碱治疗的动物中扰乱了参与突触前形式的LTP的特征明确的cAMP依赖信号通路。我们的研究结果表明，在TLE中，突触可塑性的紊乱可能会影响海马体和新皮层之间的信息流动。我们证明在毛果芸香碱治疗的动物中扰乱了参与突触前形式的LTP的特征明确的cAMP依赖信号通路。我们的研究结果表明，在TLE中，突触可塑性的紊乱可能会影响海马体和新皮层之间的信息流动。我们证明在毛果芸香碱治疗的动物中扰乱了参与突触前形式的LTP的特征明确的cAMP依赖信号通路。我们的研究结果表明，在TLE中，突触可塑性的紊乱可能会影响海马体和新皮层之间的信息流动。