Laboratory of Applied Neuroscience, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
J Neurosci. 2013 Jun 12;33(24):9963-74. doi: 10.1523/JNEUROSCI.4078-12.2013.
Damage to the medial temporal lobe impairs the encoding of new memories and the retrieval of memories acquired immediately before the damage in human. In this study, we demonstrated that artificial visuoauditory memory traces can be established in the rat auditory cortex and that their encoding and retrieval depend on the entorhinal cortex of the medial temporal lobe in the rat. We trained rats to associate a visual stimulus with electrical stimulation of the auditory cortex using a classical conditioning protocol. After conditioning, we examined the associative memory traces electrophysiologically (i.e., visual stimulus-evoked responses of auditory cortical neurons) and behaviorally (i.e., visual stimulus-induced freezing and visual stimulus-guided reward retrieval). The establishment of a visuoauditory memory trace in the auditory cortex, which was detectable by electrophysiological recordings, was achieved over 20-30 conditioning trials and was blocked by unilateral, temporary inactivation of the entorhinal cortex. Retrieval of a previously established visuoauditory memory was also affected by unilateral entorhinal cortex inactivation. These findings suggest that the entorhinal cortex is necessary for the encoding and involved in the retrieval of artificial visuoauditory memory in the auditory cortex, at least during the early stages of memory consolidation.
内侧颞叶损伤会损害人类新记忆的编码和损伤前立即获得的记忆的检索。在这项研究中，我们证明了人工视听觉记忆痕迹可以在大鼠听觉皮层中建立，并且它们的编码和检索依赖于大鼠内侧颞叶的内嗅皮层。我们使用经典条件反射协议训练大鼠将视觉刺激与听觉皮层的电刺激联系起来。在条件反射后，我们用电生理学（即听觉皮层神经元的视觉刺激诱发反应）和行为学（即视觉刺激诱导的冻结和视觉刺激引导的奖励检索）检查了联想记忆痕迹。听觉皮层中可通过电生理记录检测到的视听觉记忆痕迹的建立需要 20-30 次条件反射试验，并且单侧暂时失活内嗅皮层会阻断其建立。以前建立的视听觉记忆的检索也受到单侧内嗅皮层失活的影响。这些发现表明，在内侧颞叶损伤后，内嗅皮层对于听觉皮层中人工视听觉记忆的编码和参与记忆检索是必要的，至少在记忆巩固的早期阶段是这样。
