Offset-related brain activity in the left ventrolateral prefrontal cortex promotes long-term memory formation of verbal events

Angela Medvedeva, Rebecca Saw, Carla Silvestri, Miroslav Sirota, Giorgio Fuggetta, Giulia Galli

Research output: Contribution to journalArticlepeer-review

Abstract

BACKGROUND: Recent evidence suggests that brain activity following the offset of a stimulus during encoding contributes to long-term memory formation, however the exact mechanisms underlying offset-related encoding are still unclear.

OBJECTIVES: Here, in three repetitive transcranial magnetic stimulation studies (rTMS) we investigated offset-related activity in the left ventrolateral prefrontal cortex (VLPFC). rTMS was administered at different points in time around stimulus offset while participants encoded visually-presented words or pairs of words. The analyses focused on the effects of the stimulation on subsequent memory performance.

RESULTS: rTMS administered at the offset of the stimuli, but not during online encoding, disrupted subsequent memory performance. In Experiment 1 we found that rTMS specifically disrupted encoding mechanisms initiated by the offset of the stimuli rather than general, post-stimulus processes. Experiment 2 showed that this effect was not dependent upon rTMS-induced somatosensory effects. In a third rTMS experiment we further demonstrated a robust decline in associative memory performance when the stimulation was delivered at the offset of the word pairs, suggesting that offset-related encoding may contribute to the binding of information into an episodic memory trace.

CONCLUSIONS: The offset of the stimulus may represent an event boundary that promotes the reinstatement of the previously experienced event and episodic binding.

Original languageEnglish
Pages (from-to)564-570
Number of pages7
JournalBrain Stimulation
Volume14
Issue number3
DOIs
Publication statusPublished - 17 Mar 2021

Keywords

  • Brain Mapping
  • Humans
  • Memory, Episodic
  • Memory, Long-Term
  • Prefrontal Cortex
  • Transcranial Magnetic Stimulation

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