Bonner-Jackson Aaron, Yodkovik Naomi, Csernansky John G, Barch Deanna M
Departments of Psychology and Psychiatry, Washington University, St. Louis, MO 63130, USA.
Psychiatry Res. 2008 Oct 30;164(1):1-15. doi: 10.1016/j.pscychresns.2007.12.012. Epub 2008 Sep 14.
Individuals with schizophrenia demonstrate behavioral and neurobiological deficits in episodic memory. However, recent work suggests that episodic memory deficits in schizophrenia may be mitigated through specific encoding strategies. The current study directly compared brain activity and memory performance associated with two different verbal encoding orientations in the same group of schizophrenia participants, in order to more fully characterize the role of strategy in memory processing in this population. Participants included 18 individuals with schizophrenia and 15 healthy comparison participants. Participants encoded words under two conditions during separate fMRI scanning runs. During Incidental encoding, participants were required to make abstract/concrete judgments for each word. During Intentional encoding, participants were instructed to memorize each word for a later memory test. Free recall and a recognition task (utilizing the Remember/Know paradigm) were performed outside of the scanner. Consistent with prior work, schizophrenia participants recognized more words encoded Incidentally than Intentionally, although free recall remained substantially impaired. Schizophrenia participants were also less likely to give Remember judgments for old words and more likely to give Guess judgments for both old and new words. When functional magnetic resonance imaging data were examined, we found that Incidental encoding was associated with substantially fewer between-group differences (Control>Schizophrenia) than Intentional encoding. Furthermore, schizophrenia participants exhibited intact activity during encoding of items that were subsequently retrieved. Our results suggest that use of an Incidental encoding strategy improved recognition memory among individuals with schizophrenia and resulted in a pattern of encoding-related brain activity that was more similar to that seen in control participants. However, we found that Incidental encoding did not improve free recall in schizophrenia participants and abnormal brain activity in some regions was observed, despite improvements in recognition memory.
精神分裂症患者在情景记忆方面表现出行为和神经生物学缺陷。然而，最近的研究表明，精神分裂症的情景记忆缺陷可能通过特定的编码策略得到缓解。本研究直接比较了同一组精神分裂症参与者在两种不同语言编码方向下的大脑活动和记忆表现，以便更全面地描述策略在该人群记忆处理中的作用。参与者包括18名精神分裂症患者和15名健康对照参与者。在单独的功能磁共振成像扫描过程中，参与者在两种条件下对单词进行编码。在偶然编码期间，参与者被要求对每个单词做出抽象/具体判断。在有意编码期间，参与者被指示记住每个单词以便随后进行记忆测试。在扫描仪外进行自由回忆和识别任务（使用记住/知道范式）。与先前的研究一致，精神分裂症参与者偶然编码的单词识别数量多于有意编码的，尽管自由回忆仍然严重受损。精神分裂症参与者对旧单词做出“记住”判断的可能性也较小，对新旧单词做出“猜测”判断的可能性更大。当检查功能磁共振成像数据时，我们发现与有意编码相比，偶然编码的组间差异（对照组>精神分裂症组）显著更少。此外，精神分裂症参与者在随后被检索的项目编码过程中表现出完整的活动。我们的结果表明，使用偶然编码策略改善了精神分裂症患者的识别记忆，并导致了一种与对照组更相似的编码相关脑活动模式。然而，我们发现偶然编码并没有改善精神分裂症参与者的自由回忆，并且尽管识别记忆有所改善，但仍观察到某些区域存在异常脑活动。
