Department of Psychology, Yale University, New Haven, Connecticut 06520, USA.
J Neurosci. 2012 Mar 7;32(10):3453-61. doi: 10.1523/JNEUROSCI.5846-11.2012.
Our ability to remember new information is often compromised by competition from prior learning, leading to many instances of forgetting. One of the challenges in studying why these lapses occur and how they can be prevented is that it is methodologically difficult to "see" competition between memories as it occurs. Here, we used multi-voxel pattern analysis of human fMRI data to measure the neural reactivation of both older (competing) and newer (target) memories during individual attempts to retrieve newer memories. Of central interest was the following: (1) whether older memories were reactivated during retrieval of newer memories; (2) how reactivation of older memories related to retrieval performance; and (3) whether neural mechanisms engaged during the encoding of newer memories were predictive of neural competition experienced during retrieval. Our results indicate that older and newer visual memories were often simultaneously reactivated in ventral temporal cortex--even when target memories were successfully retrieved. Importantly, stronger reactivation of older memories was associated with less accurate retrieval of newer memories, slower mnemonic decisions, and increased activity in anterior cingulate cortex. Finally, greater activity in the inferior frontal gyrus during the encoding of newer memories (memory updating) predicted lower competition in ventral temporal cortex during subsequent retrieval. Together, these results provide novel insight into how older memories compete with newer memories and specify neural mechanisms that allow competition to be overcome and memories to be updated.
我们记住新信息的能力常常受到先前学习的竞争的影响，导致许多遗忘的情况发生。研究这些失误发生的原因以及如何预防这些失误的一个挑战是，在方法学上很难“看到”记忆之间的竞争是如何发生的。在这里，我们使用人类 fMRI 数据的多体素模式分析来测量在单独尝试检索新记忆时，较旧（竞争）和更新（目标）记忆的神经重新激活。一个核心问题是：（1）在检索新记忆时，是否会重新激活旧记忆；（2）旧记忆的重新激活与检索表现的关系；（3）在编码新记忆期间涉及的神经机制是否可以预测检索期间经历的神经竞争。我们的结果表明，即使目标记忆成功检索，较旧和更新的视觉记忆也经常同时在腹侧颞叶皮层中重新激活。重要的是，旧记忆的重新激活越强，对新记忆的检索准确性越低，记忆决策越慢，前扣带皮层的活动增加。最后，在新记忆（记忆更新）编码期间，下额前回的活动越大，随后检索期间腹侧颞叶皮层的竞争越低。总之，这些结果为旧记忆如何与新记忆竞争提供了新的见解，并说明了允许克服竞争和更新记忆的神经机制。
