Center for Vital Longevity and School of Behavioral and Brain Sciences, The University of Texas at Dallas Dallas, TX, USA.
Front Hum Neurosci. 2013 Aug 14;7:436. doi: 10.3389/fnhum.2013.00436. eCollection 2013.
fMRI was employed to investigate the role of the left inferior frontal gyrus (LIFG) in the encoding of item-item and item-context associations. On each of a series of study trials subjects viewed a picture that was presented either to the left or right of fixation, along with a subsequently presented word that appeared at fixation. Memory was tested in a subsequent memory test that took place outside of the scanner. On each test trial one of two forced choice judgments was required. For the associative test, subjects chose between the word paired with the picture at study and a word studied on a different trial. For the source test, the judgment was whether the picture had been presented on the left or right. Successful encoding of associative information was accompanied by subsequent memory effects in several cortical regions, including much of the LIFG. By contrast, successful source encoding was selectively associated with a subsequent memory effect in right fusiform cortex. The finding that the LIFG was enhanced during successful associative, but not source, encoding is interpreted in light of the proposal that subsequent memory effects are localized to cortical regions engaged by the on-line demands of the study task.
功能性磁共振成像（fMRI）被用来研究左额下回（LIFG）在项目-项目和项目-语境关联编码中的作用。在一系列研究试验中，每个试验中，受试者会看到一张图片，图片要么出现在注视点的左边，要么出现在注视点的右边，同时还会出现一个随后出现在注视点的单词。在随后的记忆测试中，会对记忆进行测试，而这个测试是在扫描仪之外进行的。在每个测试试验中，需要做出两个强制选择判断之一。对于联想测试，受试者在学习时与图片配对的单词和在不同试验中学习的单词之间进行选择。对于来源测试，判断是图片是出现在左边还是右边。在几个皮质区域，包括大部分的左额下回，成功的联想信息编码伴随着随后的记忆效应。相比之下，成功的来源编码与右侧梭状回的随后记忆效应选择性相关。LIFG 在成功的联想编码过程中增强，但在来源编码过程中没有增强的发现，这是根据这样一种假设来解释的，即随后的记忆效应被定位在参与在线研究任务的皮质区域。
