Good vibrations - An observational study of real-life stress induced by a stage performance

Abstract

The fate of a memory is partly determined at initial encoding. However, the behavioral consequences of memory formation are oftentested only once and shortly after learning, which leaves the neuronal predictors for the formation of durable memories largely unknown.Here, we hypothesized that durable memory formation (as opposed to weak or no memory formation) is reflected through increasedactivation in the medial temporal lobes and prefrontal cortex, and more consistent processing (i.e., stronger pattern similarity) acrossencoding material. Thirty-four human subjects studied unique picture–location associations while undergoing fMRI and performed acued recall test immediately after study as well as 48 h later. Associative memories were defined as “weak” if they were retrieved duringthe immediate test only. Conversely, “durable” memories persisted also after 48 h. The posterior cingulate cortex showed increasedpattern similarity during successful memory formation, independent of the eventual durability. For durable memory encoding, we foundincreased activation in medial and inferior temporal, prefrontal, and parietal regions. This was accompanied by stronger pattern simi-larity in lateral prefrontal and parietal regions, as well as in anterior and posterior midline structures that were also engaged during latermemory retrieval. Thus, we show that pattern similarity, or consistent processing, in the posterior cingulate cortex predicts associativememory formation at encoding. If this is paralleled by additional activation increases in regions typically related to encoding, and byconsistent processing in regions involved in later retrieval, formed memories appear durable for at least 48 h.