University of California, San Diego, La Jolla, CA, USA.
J Cogn Neurosci. 2010 Jan;22(1):109-23. doi: 10.1162/jocn.2009.21190.
fMRI studies of recognition memory have often been interpreted to mean that the hippocampus selectively subserves recollection and that adjacent regions selectively subserve familiarity. Yet, many of these studies have confounded recollection and familiarity with strong and weak memories. In a source memory experiment, we compared correct source judgments (which reflect recollection) and incorrect source judgments (often thought to reflect familiarity) while equating for old-new memory strength by including only high-confidence hits in the analysis. Hippocampal activity associated with both correct source judgments and incorrect source judgments exceeded the activity associated with forgotten items and did so to a similar extent. Further, hippocampal activity was greater for high-confidence old decisions relative to forgotten items even when source decisions were at chance. These results identify a recollection signal in the hippocampus and may identify a familiarity signal as well. Similar results were obtained in the parahippocampal gyrus. Unlike in the medial temporal lobe, activation in prefrontal cortex increased differentially in association with source recollection.
功能磁共振成像研究的识别记忆通常被解释为海马体选择性地支持回忆,而相邻区域选择性地支持熟悉度。然而,许多这些研究将回忆和熟悉度与强记忆和弱记忆混淆在一起。在源记忆实验中,我们通过仅在分析中包含高置信度命中,来比较正确的源判断(反映回忆)和错误的源判断(通常被认为反映熟悉度),同时平衡新旧记忆强度。与遗忘项目相比,与正确的源判断和错误的源判断相关的海马体活动都超过了与遗忘项目相关的活动,而且程度相似。此外,即使源判断处于随机状态,与遗忘项目相比,高置信度的旧决策的海马体活动也更大。这些结果在海马体中确定了一个回忆信号,并且可能也确定了一个熟悉度信号。在旁海马回中也得到了类似的结果。与内侧颞叶不同,前额叶皮层的激活与源回忆相关,差异增加。