Distinct replay signatures for prospective decision-making and memory preservation

Description: [Wimmer, Liu, McNamee, Dolan (2023) PNAS] Theories of neural replay propose that it supports a range of functions, most prominently planning and memory consolidation. Here, we test the hypothesis that distinct signatures of replay in the same task are related to model-based decision-making (‘planning’) and memory consolidation (‘preservation’). We designed a reward learning task wherein participants utilized structure knowledge for ‘model-based’ evaluation, while at the same time maintaining knowledge of two independent and randomly alternating task environments. Using magnetoencephalography (MEG) and multivariate analysis, we first identified temporally compressed sequential reactivation, or replay, both prior to decisions and following reward feedback. Prospective replay strength was enhanced for the current task-relevant environment when the benefits of a model-based planning strategy were higher. Following reward receipt, replay for the alternative, ‘distal’ task environment was enhanced as a function of decreasing recency of experience with that environment, consistent with a memory preservation role. Critically, these planning and memory preservation relationships were selective to pre-choice and post-feedback periods. Our results provide new support for key theoretical proposals for the role of replay and demonstrate that the relative strength of planning and memory-related signals are modulated by on-going computational and task demands.

Related article: http://doi.org/10.1073/pnas.2205211120

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