Format

Send to

Choose Destination
J Neurosci. 2014 Oct 15;34(42):13998-4005. doi: 10.1523/JNEUROSCI.2535-14.2014.

Temporal memory is shaped by encoding stability and intervening item reactivation.

Author information

1
Department of Psychology and.
2
Department of Psychology and Center for Neural Science, New York University, New York, New York 10003 lila.davachi@nyu.edu.

Abstract

Making sense of previous experience requires remembering the order in which events unfolded in time. Prior work has implicated the hippocampus and medial temporal lobe cortex in memory for temporal information associated with individual episodes. However, the processes involved in encoding and retrieving temporal information across extended sequences is relatively poorly understood. Here we used fMRI during the encoding and retrieval of extended sequences to test specific predictions about the type of information used to resolve temporal order and the role of the hippocampus in this process. Participants studied sequences of images of celebrity faces and common objects followed by a recency discrimination test. The main conditions of interest were pairs of items that had been presented with three intervening items, half of which included an intervening category shift. During encoding, hippocampal pattern similarity across intervening items was associated with subsequent successful order memory. To test for evidence of associative retrieval, we trained a classifier to discriminate encoding patterns associated with faces versus objects and applied the classifier on fMRI patterns during recency discrimination. We found evidence that the category content of intervening items was reactivated during recency judgments, and this was related to hippocampal encoding-retrieval similarity. A follow-up behavioral priming experiment revealed additional evidence for intervening item reinstatement during temporal order judgments. Reinstatement did not differ according to whether the items occurred within a single context or across context boundaries. Thus, these data suggest that inter-item associative encoding and retrieval mediated by the hippocampus contribute to temporal order memory.

KEYWORDS:

MVPA; event segmentation; fMRI; hippocampus; temporal order

PMID:
25319696
PMCID:
PMC4198540
DOI:
10.1523/JNEUROSCI.2535-14.2014
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center