Bernstein Lori J, Beig Sania, Siegenthaler Amy L, Grady Cheryl L
Rotman Research Institute, Baycrest Centre for Geriatric Care, University of Toronto, 3560 Bathurst Street, Ont., M6A 2EI, Toronto, Canada.
Neuropsychologia. 2002;40(1):86-98. doi: 10.1016/s0028-3932(01)00070-7.
Encoding and recognition of unfamiliar faces in young adults were examined using positron emission tomography to determine whether different encoding strategies would lead to encoding/retrieval differences in brain activity. Three types of encoding were compared: a 'deep' task (judging pleasantness/unpleasantness), a 'shallow' task (judging right/left orientation), and an intentional learning task in which subjects were instructed to learn the faces for a subsequent memory test but were not provided with a specific strategy. Memory for all faces was tested with an old/new recognition test. A modest behavioral effect was obtained, with deeply-encoded faces being recognized more accurately than shallowly-encoded or intentionally-learned faces. Regardless of encoding strategy, encoding activated a primarily ventral system including bilateral temporal and fusiform regions and left prefrontal cortices, whereas recognition activated a primarily dorsal set of regions including right prefrontal and parietal areas. Within encoding, the type of strategy produced different brain activity patterns, with deep encoding being characterized by left amygdala and left anterior cingulate activation. There was no effect of encoding strategy on brain activity during the recognition conditions. Posterior fusiform gyrus activation was related to better recognition accuracy in those conditions encouraging perceptual strategies, whereas activity in left frontal and temporal areas correlated with better performance during the 'deep' condition. Results highlight three important aspects of face memory: (1) the effect of encoding strategy was seen only at encoding and not at recognition; (2) left inferior prefrontal cortex was engaged during encoding of faces regardless of strategy; and (3) differential activity in fusiform gyrus was found, suggesting that activity in this area is not only a result of automatic face processing but is modulated by controlled processes.
利用正电子发射断层扫描技术，研究了年轻人对陌生面孔的编码和识别，以确定不同的编码策略是否会导致大脑活动在编码/检索方面的差异。比较了三种编码方式：一种“深度”任务（判断愉悦/不愉悦）、一种“浅层”任务（判断左右方向），以及一种有意学习任务，即指示受试者学习面孔以便后续进行记忆测试，但未提供具体策略。通过旧/新识别测试对所有面孔的记忆进行了检测。获得了适度的行为效应，深度编码的面孔比浅层编码或有意学习的面孔识别得更准确。无论编码策略如何，编码激活的主要是一个腹侧系统，包括双侧颞叶和梭状回区域以及左侧前额叶皮质，而识别激活的主要是一组背侧区域，包括右侧前额叶和顶叶区域。在编码过程中，策略类型产生了不同的大脑活动模式，深度编码的特征是左侧杏仁核和左侧前扣带回激活。在识别条件下，编码策略对大脑活动没有影响。在那些鼓励采用感知策略的条件下，梭状回后部激活与更好的识别准确性相关，而在“深度”条件下，左侧额叶和颞叶区域的活动与更好的表现相关。结果突出了面孔记忆的三个重要方面：（1）编码策略的影响仅在编码时可见，而在识别时不可见；（2）无论策略如何，在面孔编码过程中左侧前额叶下回均会参与；（3）发现梭状回存在差异活动，表明该区域的活动不仅是自动面孔处理的结果，还受控制过程的调节。
