Output Planning at the Input Stage: Action Imprinting for Future Memory-Guided Behaviour

Working memory serves as the buffer between past sensations and future behaviour, making it vital to understand not only how we encode and retain information in memory but also how we plan for its upcoming use. We ask when prospective action goals emerge alongside the encoding and retention of detailed sensory information in working memory – whether future action plans emerge gradually during memory delays, or are brought into memory early, in tandem with sensory encoding. To address this, we tracked neural planning for prospective actions in a working-memory task in which detailed visual shape information was linked to specific manual actions after a delay. We show that prospective action plans in human motor cortex emerge early alongside the selective encoding of visual information into memory. This ‘action imprinting’ (1) precedes a second stage of action preparation that adapts to the time of expected memory utilisation, (2) occurs even in face of an intervening motor task, and (3) predicts visual-memory-guided behaviour several seconds later. By bringing prospective action plans into working memory at an early stage, the brain creates a dual (visual-motor) memory code that can make memories more effective and robust for serving future behaviour.