Delay-dependent contributions of medial temporal lobe regions to episodic memory retrieval

  title={Delay-dependent contributions of medial temporal lobe regions to episodic memory retrieval},
  author={Maureen Ritchey and Maria E. Montchal and Andrew P. Yonelinas and Charan Ranganath},
The medial temporal lobes play an important role in episodic memory, but over time, hippocampal contributions to retrieval may be diminished. However, it is unclear whether such changes are related to the ability to retrieve contextual information, and whether they are common across all medial temporal regions. Here, we used functional neuroimaging to compare neural responses during immediate and delayed recognition. Results showed that recollection-related activity in the posterior hippocampus… 

Differential activation of the medial temporal lobe during item and associative memory across time

Time-dependent memory transformation along the hippocampal anterior–posterior axis

It is reported that anterior activity supporting memory specificity declines over time while posterior activity patterns carrying gist representations remain more stable, indicating that, in addition to the well-known systems consolidation from hippocampus to neocortex, there are changes within the hippocampus that are crucial for the temporal dynamics of memory.

Concurrent feature-specific reactivation within the hippocampus and neocortex facilitates episodic memory retrieval

The findings show large individual differences in the features underlying visual memory and suggest that the anterior and posterior hippocampus represents gist-like and detailed features, respectively, respectively.

Age-Related Increases in Posterior Hippocampal Granularity Are Associated with Remote Detailed Episodic Memory in Development

Examining time signatures in individual hippocampal voxels is used to reveal regionally specific differences in the distinctiveness of temporal activation profiles across development, and suggests that the posterior hippocampus gradually builds the capacity to support detailed episodic recall.

Differentiation of Human Medial Prefrontal Cortex Activity Underlies Long-Term Resistance to Forgetting in Memory

The results show that learning information across days leads to differentiated MPFC memory representations, reducing forgetting after 1 week, and suggest this arises from persistent interactions between MPFC and hippocampus, which supports robust long-term memory via persistent MPFC–hippocampal interactions.

A contextual binding theory of episodic memory: systems consolidation reconsidered

It is argued that forgetting is largely due to contextual interference, episodic memory remains dependent on the hippocampus across time, contextual drift produces post-encoding activity and sleep benefits memory by reducing contextual interference.

Changes in patterns of neural activity underlie a time-dependent transformation of memory in rats and humans

It is found that context-specific memories in rats, and naturalistic episodic memories in humans, lose precision over time and activity in the hippocampus decreases, but if, however, the retrieved memories retain contextual or perceptual detail, the hippocampus is engaged similarly at recent and remote timepoints.



Multiple routes to memory: Distinct medial temporal lobe processes build item and source memories

This work used event-related functional MRI to examine the relation between activation in distinct medial temporal lobe subregions during memory formation and the ability to later recognize an item as previously encountered and later recollect specific contextual details about the prior encounter.

Medial Temporal Lobe Coding of Item and Spatial Information during Relational Binding in Working Memory

The integrity of multivoxel patterns in the right anterior hippocampus across encoding and delay periods was predictive of accurate short-term memory for object–location relationships, and results are consistent with parallel processing of item and spatial context information by PRC and PHC, respectively, and the binding ofitem and context by the hippocampus.

Medial temporal lobe contributions to cued retrieval of items and contexts

Neural similarity between encoding and retrieval is related to memory via hippocampal interactions.

The novel prediction that encoding-retrieval similarity can be observed and related to memory at the level of individual items is tested and speaks to the promise of pattern similarity measures for evaluating memory representations and hippocampal-cortical interactions.

Item, context and relational episodic encoding in humans

  • L. Davachi
  • Psychology, Biology
    Current Opinion in Neurobiology
  • 2006

FMRI activity in the medial temporal lobe during recognition memory as a function of study‐test interval

The phenomenon of temporally graded retrograde amnesia (loss of information acquired before the onset of amnesia) suggests that the hippocampus, and possibly other medial temporal lobe (MTL)

The Medial Temporal Lobe Supports Conceptual Implicit Memory

Hippocampal involvement in recollection but not familiarity across time: A prospective study

Findings support the idea that the MTL is a dual memory system and indicate a lasting hippocampal involvement in the recollection component of recognition memory and a decrease of perirhinal cortex activation associated with familiarity for time periods up to 6 weeks after new learning.

The role of recollection and familiarity in the functional differentiation of the medial temporal lobes

There has been disagreement about whether recall/recollection is primarily mediated by the hippocampus and familiarity by the evolutionarily newer MTL cortices or whether the MTL mediates these kinds of memory in an integrated, homogeneous fashion.