Gaynor Leslie S, Johnson Sarah A, Mizell Jack Morgan, Campos Keila T, Maurer Andrew P, Bauer Russell M, Burke Sara N
Department of Neuroscience, University of Florida.
McKnight Brain Institute, University of Florida.
Behav Neurosci. 2018 Jun;132(3):138-151. doi: 10.1037/bne0000246.
The perirhinal cortex (PRC) supports associative memory and perception, and PRC dysfunction impairs animals' abilities to associate stimulus features across sensory modalities. PRC damage also leads to deficits in discriminating between stimuli that share features. Although PRC-dependent stimulus discrimination has been shown to be impaired with advanced age, data regarding the abilities of older adults and other animals to form PRC-dependent associations have been equivocal. Moreover, the extent to which similar neural computations within the PRC support associative memory versus discrimination abilities have not been directly examined. In the current study, young and aged rats were cross-characterized on two PRC-dependent crossmodal object recognition (CMOR) tasks to test associative memory, and a LEGO object discrimination task. In the CMOR tasks, rats were familiarized with an object with access to tactile input and then tested for recognition with visual input only. The relative exploration time of novel versus familiar objects indicated that aged rats showed preference for the novel over familiar object with and without an epoch of multimodal preexposure to the familiar object prior to the testing session. Furthermore, crossmodal recognition performance between young and aged rats was not significantly different. In contrast, for the LEGO object discrimination task, aged rats were impaired relative to young rats. Notably, aged rats that performed poorly on the LEGO object discrimination task had better performance on the CMOR tasks. The dissociation of discrimination and association abilities with age suggests that these behaviors rely on distinct neural computations within PRC-medial temporal lobe circuit. (PsycINFO Database Record
嗅周皮质（PRC）支持联想记忆和感知，PRC功能障碍会损害动物跨感觉模态关联刺激特征的能力。PRC损伤还会导致在区分具有共同特征的刺激方面出现缺陷。尽管已表明依赖PRC的刺激辨别能力会随着年龄增长而受损，但关于老年人和其他动物形成依赖PRC的关联的能力的数据一直不明确。此外，PRC内类似神经计算在多大程度上支持联想记忆与辨别能力尚未得到直接研究。在当前研究中，对年轻和老年大鼠在两项依赖PRC的跨模态物体识别（CMOR）任务上进行交叉特征分析以测试联想记忆，并进行了乐高物体辨别任务。在CMOR任务中，让大鼠通过触觉输入熟悉一个物体，然后仅用视觉输入进行识别测试。新奇物体与熟悉物体的相对探索时间表明，无论在测试前是否有一个阶段对熟悉物体进行多模态预暴露，老年大鼠都表现出对新奇物体而非熟悉物体的偏好。此外，年轻和老年大鼠之间的跨模态识别表现没有显著差异。相比之下，在乐高物体辨别任务中，老年大鼠相对于年轻大鼠表现受损。值得注意的是，在乐高物体辨别任务中表现较差的老年大鼠在CMOR任务中表现更好。辨别能力和关联能力随年龄的分离表明，这些行为依赖于PRC-内侧颞叶回路内不同的神经计算。（PsycINFO数据库记录）
