Department of Psychiatry, University of California, San Diego, La Jolla, California 92093, USA.
J Neurosci. 2011 Nov 2;31(44):15693-702. doi: 10.1523/JNEUROSCI.3438-11.2011.
Recognition memory is thought to consist of two component processes--recollection and familiarity. It has been suggested that the hippocampus supports recollection, while adjacent cortex supports familiarity. However, the qualitative experiences of recollection and familiarity are typically confounded with a quantitative difference in memory strength (recollection > familiarity). Thus, the question remains whether the hippocampus might in fact support familiarity-based memories whenever they are as strong as recollection-based memories. We addressed this problem in a novel way by using the Remember/Know procedure, which allowed us to explicitly match the confidence and accuracy of Remember and Know decisions. As in earlier studies, recollected items had higher accuracy and confidence than familiar items, and hippocampal activity was higher for recollected items than for familiar items. Furthermore, hippocampal activity was similar for familiar items, misses, and correct rejections. When the accuracy and confidence of recollected and familiar items were matched, the findings were dramatically different. Hippocampal activity was now similar for recollected and familiar items. Importantly, hippocampal activity was also greater for familiar items than for misses or correct rejections (as well as for recollected items vs misses or correct rejections). Our findings suggest that the hippocampus supports both recollection and familiarity when memories are strong.
再认记忆被认为由两个组成部分——记忆提取和熟悉度。有人认为海马体支持记忆提取，而相邻的皮质支持熟悉度。然而，记忆提取和熟悉度的定性体验通常与记忆强度的定量差异（记忆提取>熟悉度）混淆。因此，问题仍然是，当基于熟悉度的记忆与基于记忆提取的记忆一样强时，海马体是否实际上可能支持基于熟悉度的记忆。我们通过使用“记得/知道”程序以一种新颖的方式解决了这个问题，该程序允许我们明确匹配“记得”和“知道”决策的信心和准确性。与早期研究一样，被回忆的项目比熟悉的项目具有更高的准确性和信心，并且被回忆的项目的海马体活动高于熟悉的项目。此外，海马体活动对于熟悉的项目、错过的项目和正确的拒绝项目相似。当回忆和熟悉项目的准确性和信心相匹配时，结果大不相同。现在，海马体活动对于被回忆的项目和熟悉的项目相似。重要的是，海马体活动对于熟悉的项目也大于错过的项目或正确的拒绝项目（以及对于回忆的项目与错过的项目或正确的拒绝项目相比）。我们的研究结果表明，当记忆较强时，海马体既支持记忆提取，也支持熟悉度。
