Perception is an intricate interplay between feedforward visual input and internally generated feedback signals that comprise concurrent contextual and time-distant mnemonic (episodic and semantic) information. Yet, an unresolved question is how the composition of feedback signals changes across the lifespan and to what extent feedback signals undergo age-related dedifferentiation, that is, a decline in neural specificity. Previous research on this topic has focused on feedforward perceptual representation and episodic memory reinstatement, suggesting reduced fidelity of neural representations at the item and category levels. In this fMRI study, we combined an occlusion paradigm that filters feedforward input to the visual cortex and multivariate analysis techniques to investigate the information content in cortical feedback, focusing on age-related differences in its composition. We further asked to what extent differentiation in feedback signals (in the occluded region) is correlated to differentiation in feedforward signals. Comparing younger (18–30 years) and older female and male adults (65–75 years), we found that contextual but not mnemonic feedback was prone to age-related dedifferentiation. Semantic feedback signals were even better differentiated in older adults, highlighting the growing importance of generalized knowledge across ages. We also found that differentiation in feedforward signals was correlated with differentiation in episodic but not semantic feedback signals. Our results provide evidence for age-related adjustments in the composition of feedback signals and underscore the importance of examining dedifferentiation in aging for both feedforward and feedback processing.

感知是前馈视觉输入和内部生成的反馈信号之间复杂的相互作用，其中包括并发的上下文和时间遥远的助记符（情景和语义）信息。然而，一个尚未解决的问题是反馈信号的组成在整个生命周期中如何变化，以及反馈信号在多大程度上经历了与年龄相关的去分化，即神经特异性的下降。先前关于该主题的研究主要集中在前馈感知表征和情景记忆恢复上，表明项目和类别级别的神经表征的保真度降低。在这项功能磁共振成像研究中，我们结合了过滤视觉皮层前馈输入的遮挡范式和多元分析技术来研究皮层反馈中的信息内容，重点关注其组成中与年龄相关的差异。我们进一步询问反馈信号（在遮挡区域中）的差异在多大程度上与前馈信号的差异相关。比较年轻（18-30 岁）和年长女性和男性（65-75 岁），我们发现上下文反馈而非记忆反馈更容易出现与年龄相关的去分化。老年人的语义反馈信号甚至可以更好地区分，这凸显了跨年龄段的广义知识日益增长的重要性。我们还发现前馈信号的分化与情景反馈信号的分化相关，但与语义反馈信号无关。我们的结果为反馈信号组成中与年龄相关的调整提供了证据，并强调了检查衰老中的去分化对于前馈和反馈处理的重要性。