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.
Cortico-hippocampal network connections support the multidimensional quality of episodic memory
These findings demonstrate not only how hippocampal-cortical connections reconfigure during episodic retrieval, but how such dynamic interactions might flexibly support the multidimensional quality of remembered events.
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.


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 Activity during Source Retrieval Reflects Information Type, not Memory Strength
Results showed that encoding color information as an item detail improved source recognition in amnesic patients with recollection deficits, and qualitatively different patterns of results observed in PRc and hippocampus/PHc are consistent with the idea that different MTL regions process different types of episodic information.
Medial temporal lobe contributions to cued retrieval of items and contexts
A unified framework for the functional organization of the medial temporal lobes and the phenomenology of episodic memory
Findings from physiology, functional imaging, and lesion studies in humans, monkeys, and rodents relevant to the roles of medial temporal lobe subregions in recognition memory, as well as in short‐term memory and perception are reviewed.
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