University of California, San Diego, CA, USA.
J Cogn Neurosci. 2013 Feb;25(2):219-33. doi: 10.1162/jocn_a_00335. Epub 2012 Nov 28.
Neuroimaging studies of episodic memory retrieval have revealed activations in the human frontal, parietal, and medial-temporal lobes that are associated with memory strength. However, it remains unclear whether these brain responses are veritable signals of memory strength or are instead regulated by concomitant subcomponents of retrieval such as retrieval effort or mental search. This study used event-related fMRI during cued recall of previously memorized word-pair associates to dissociate brain responses modulated by memory search from those modulated by the strength of a recalled memory. Search-related deactivations, dissociated from activity due to memory strength, were observed in regions of the default network, whereas distinctly strength-dependent activations were present in superior and inferior parietal and dorsolateral PFC. Both search and strength regulated activity in dorsal anterior cingulate and anterior insula. These findings suggest that, although highly correlated and partially subserved by overlapping cognitive control mechanisms, search and memory strength engage dissociable regions of frontoparietal attention and default networks.
神经影像学研究表明，在人类的额叶、顶叶和内侧颞叶中存在与记忆强度相关的激活。然而，目前尚不清楚这些大脑反应是否是记忆强度的真实信号，或者它们是否受到检索过程中的伴随子成分（如检索努力或心理搜索）的调节。本研究使用事件相关 fMRI，在被试回忆先前记忆的单词对联想时，将受记忆搜索调节的大脑反应与受回忆记忆强度调节的大脑反应区分开来。从记忆强度引起的活动中分离出来的与搜索相关的去激活，出现在默认网络的区域中，而在顶叶下和背外侧 PFC 中存在明显的与强度相关的激活。在背侧前扣带和前岛叶中，搜索和强度都调节着活动。这些发现表明，尽管搜索和记忆强度高度相关，并且部分受到重叠的认知控制机制的支持，但它们涉及到额顶叶注意力和默认网络的不同区域。
