# The Effects of External Cue Overlap and Internal Goals on Selective Memory Retrieval as Revealed by Electroencephalographic (EEG) Neural Pattern Reinstatement

## TL;DR

This study shows how brain activity during memory retrieval is influenced by both external cues and internal goals, using EEG to track neural patterns.

## Contribution

The study reveals that neural reinstatement during retrieval depends on cue overlap and retrieval goals, with distinct patterns for proactive and reactive memory selection.

## Key findings

- Neural reinstatement occurs around 500 ms post-stimulus and is target-selective when cues overlap with targets.
- When cues overlap with non-targets, neural reinstatement is reversed, showing greater activity for non-targets.
- Proactive reinstatement was observed with word cues but not with picture cues, indicating goal-directed control varies by cue type.

## Abstract

For past experiences to guide our actions, we need to retrieve the relevant memories. Here, we used electroencephalography (EEG) to investigate how memories are selected for retrieval and to test how current goals and external retrieval cues drive selection during the retrieval cascade. We analysed data from two studies in which people studied objects in picture or auditory word formats and later recalled them using either written words (Experiment 1, n = 28) or line drawings (Experiment 2, n = 28) as retrieval cues. We used multivariate decoding to quantify the reinstatement of study phase neural patterns when people successfully identified items that had been studied in a format currently designated as targeted, compared with non‐targeted items. Neural reinstatement emerged at around 500 ms post‐stimulus, like the established left parietal event‐related potential (ERP) signature of recollection. Reinstatement was target‐selective (greater for targets than non‐targets) when test cues overlapped more with targets, a pattern previously shown for the left parietal ERP. In contrast, when cues overlapped more with non‐targets, neural reinstatement was reversed—greater for non‐targets—unlike the left parietal ERP. We also tested for goal‐directed mental reinstatement proposed to guide selection prior to retrieval cues. When words were cues, there was strong evidence of this proactive reinstatement, but it was not detected when pictures were cues. Together, the data suggest that selection can act at multiple stages of memory retrieval and depends on both external cues and goal‐directed control.

This EEG study used multivariate decoding in humans to investigate how memories are selected when retrieval goals vary. The results showed that EEG neural patterns reinstating studied information tracked the external retrieval cues, while the left parietal ERP typically associated with successful retrieval also reflected people's current retrieval goals. The data implicate multiple stages in goal‐dependent selection during episodic retrieval.