Division of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London W12 0NN, United Kingdom.
Ann Neurol. 2013 Feb;73(2):294-302. doi: 10.1002/ana.23789. Epub 2012 Dec 31.
Episodic memory encoding of a verbal message depends upon initial registration, which requires sustained auditory attention followed by deep semantic processing of the message. Motivated by previous data demonstrating modulation of auditory cortical activity during sustained attention to auditory stimuli, we investigated the response of the human auditory cortex during encoding of sentences to episodic memory. Subsequently, we investigated this response in patients with mild cognitive impairment (MCI) and probable Alzheimer's disease (pAD).
Using functional magnetic resonance imaging, 31 healthy participants were studied. The response in 18 MCI and 18 pAD patients was then determined, and compared to 18 matched healthy controls. Subjects heard factual sentences, and subsequent retrieval performance indicated successful registration and episodic encoding.
The healthy subjects demonstrated that suppression of auditory cortical responses was related to greater success in encoding heard sentences; and that this was also associated with greater activity in the semantic system. In contrast, there was reduced auditory cortical suppression in patients with MCI, and absence of suppression in pAD. Administration of a central cholinesterase inhibitor (ChI) partially restored the suppression in patients with pAD, and this was associated with an improvement in verbal memory.
Verbal episodic memory impairment in AD is associated with altered auditory cortical function, reversible with a ChI. Although these results may indicate the direct influence of pathology in auditory cortex, they are also likely to indicate a partially reversible impairment of feedback from neocortical systems responsible for sustained attention and semantic processing.
言语信息的情节记忆编码依赖于初始登记，这需要持续的听觉注意力，然后对信息进行深度语义处理。先前的数据表明，在持续注意听觉刺激时，听觉皮层活动会发生调制，这激发了我们对人类听觉皮层在情节记忆编码过程中的反应的研究。随后，我们研究了轻度认知障碍（MCI）和可能的阿尔茨海默病（pAD）患者的这种反应。
使用功能磁共振成像，对 31 名健康参与者进行了研究。然后确定了 18 名 MCI 和 18 名 pAD 患者的反应，并与 18 名匹配的健康对照组进行了比较。受试者听到事实性句子，随后的检索表现表明成功地登记和情节编码。
健康受试者表明，听觉皮层反应的抑制与听到的句子编码的更大成功有关；并且这也与语义系统的更大活动有关。相比之下，MCI 患者的听觉皮层抑制减少，pAD 患者则没有抑制。给予中枢胆碱酯酶抑制剂（ChI）部分恢复了 pAD 患者的抑制作用，这与言语记忆的改善有关。
AD 中的言语情节记忆损伤与听觉皮层功能改变有关，ChI 可逆转这种改变。尽管这些结果可能表明病理学对听觉皮层的直接影响，但它们也可能表明负责持续注意力和语义处理的新皮层系统的部分可逆损伤。
