The effect of stress on memory for temporal context

Abstract

Trauma memories can appear dissociated from their original temporal context, and are often relived as they occur in the here-and-now. Potentially these temporal distortions already occur during encoding of the aversive experience as a consequence of stress. Here, 86 participants were subjected to either a stress or control induction, after which they learned the temporal structure of four virtual days. In these virtual days, time was scaled and participants could use clock cues to construe the passage of time within a day. We examined whether stress causes a shift in the learning strategy from one based on virtual time to one based on event sequence. Our results do not show a discernible impact of stress on memory for temporal context, in terms of both sequence memory and more fine-grained representations of time. The stress groups showed more extreme performance trajectories, either good or poor, across all measures. However, as time estimations were overall quite poor it is unclear to what extent this reflected a true strategy shift. Future avenues of research that can build on these findings are discussed.

Structuring time: The hippocampus constructs sequence memories that generalize temporal relations across experiences

“…The constructed virtual time of an event tended to be overestimated when the events occupying the same sequence position in the other sequences took place late relative to the event in question, and vice versa when the other events occurred relatively early. In an independent group of participants 66 , we replicated this generalization bias (Figure 8D, Supplemental Figure 10B; summary statistics: t 45 =11.30, p<0.001, d=1.64, 95% CI [1.23, 2.13]; mixed model: χ 2 (1)= 53.74, p<0.001, Supplemental Figure 4QR, Supplemental Table 17), confirming the influence of generalized knowledge about the sequences on event time construction. One possibility is that structural knowledge about the sequences biases the construction of specific event times, in particular when uncertainty about the virtual time of events is high.…”

“…D . The generalization bias in event time construction through structural knowledge was replicated in an independent sample (n=46) based on Montijn et al 66 . Data shown as in B .…”

“…To replicate the results from this exploratory analysis, we conducted the same analysis in an independent group of participants. These participants (n=46) constituted the control groups of a behavioral experiment testing the effect of stress induction on temporal memory 66 . They underwent the same learning task as described above with the only difference being the duration of this learning phase (4 rather than 7 mini-blocks of training).…”

“…The timeline task was administered on the day after learning. The procedures are described in detail in Montijn et al 66 . The data from this independent sample are shown in Figure 8D and Supplemental Figure 10B.…”

Integrating and fragmenting memories under stress and alcohol

“…It also helps broaden the ways in which integration or fragmentation may be influenced by stress and contribute to subsequent adaptive behavior. For example, although a long history of work indicates that stress leads to fragmented associations of features and context, or memory representations ( Bedard-Gilligan and Zoellner, 2012 ; Brewin et al, 2010 ; Stout et al, 2018 ), emergent findings suggest that stress may enhance feature binding along with links to the underlying spatial geometry and temporal structure ( Goldfarb et al, 2019 ; Meyer et al, 2013 ; Montijn et al, 2023 ). We discuss how stress can enhance the linking of these distinct events separated by time and promote integration with overarching abstracted knowledge or comprehension structures.…”