Karanian Jessica M, Slotnick Scott D
Department of Psychology, Boston College, Chestnut Hill, MA, USA.
Department of Psychology, Boston College, Chestnut Hill, MA, USA.
Cortex. 2017 Jun;91:79-88. doi: 10.1016/j.cortex.2017.02.007. Epub 2017 Feb 24.
The role of the parahippocampal cortex is currently a topic of debate. One view posits that the parahippocampal cortex specifically processes spatial layouts and sensory details (i.e., the visual-spatial processing view). In contrast, the other view posits that the parahippocampal cortex more generally processes spatial and non-spatial contexts (i.e., the general contextual processing view). A large number of studies have found that true memories activate the parahippocampal cortex to a greater degree than false memories, which would appear to support the visual-spatial processing view as true memories are typically associated with greater visual-spatial detail than false memories. However, in previous studies, contextual details were also greater for true memories than false memories. Thus, such differential activity in the parahippocampal cortex may have reflected differences in contextual processing, which would challenge the visual-spatial processing view. In the present functional magnetic resonance imaging (fMRI) study, we employed a source memory paradigm to investigate the functional role of the parahippocampal cortex during true memory and false memory for contextual information to distinguish between the visual-spatial processing view and the general contextual processing view. During encoding, abstract shapes were presented to the left or right of fixation. During retrieval, old shapes were presented at fixation and participants indicated whether each shape was previously on the "left" or "right" followed by an "unsure", "sure", or "very sure" confidence rating. The conjunction of confident true memories for context and confident false memories for context produced activity in the parahippocampal cortex, which indicates that this region is associated with contextual processing. Furthermore, the direct contrast of true memory and false memory produced activity in the visual cortex but did not produce activity in the parahippocampal cortex. The present evidence suggests that the parahippocampal cortex is associated with general contextual processing rather than only being associated with visual-spatial processing.
海马旁皮质的作用目前是一个争论的话题。一种观点认为，海马旁皮质专门处理空间布局和感官细节（即视觉空间加工观点）。相比之下，另一种观点认为，海马旁皮质更普遍地处理空间和非空间背景（即一般背景加工观点）。大量研究发现，真实记忆比虚假记忆更能激活海马旁皮质，这似乎支持了视觉空间加工观点，因为真实记忆通常比虚假记忆与更多的视觉空间细节相关联。然而，在先前的研究中，真实记忆的背景细节也比虚假记忆更多。因此，海马旁皮质的这种差异活动可能反映了背景加工的差异，这将对视觉空间加工观点提出挑战。在本功能磁共振成像（fMRI）研究中，我们采用源记忆范式来研究海马旁皮质在对背景信息的真实记忆和虚假记忆过程中的功能作用，以区分视觉空间加工观点和一般背景加工观点。在编码过程中，抽象形状呈现在注视点的左侧或右侧。在检索过程中，旧形状呈现在注视点处，参与者指出每个形状之前是在“左侧”还是“右侧”，然后给出“不确定”“确定”或“非常确定”的信心评级。对背景的自信真实记忆和对背景的自信虚假记忆的结合在海马旁皮质产生了活动，这表明该区域与背景加工有关。此外，真实记忆和虚假记忆的直接对比在视觉皮层产生了活动，但在海马旁皮质没有产生活动。目前的证据表明，海马旁皮质与一般背景加工有关，而不仅仅与视觉空间加工有关。
