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

  title={Multiple routes to memory: Distinct medial temporal lobe processes build item and source memories},
  author={Lila Davachi and Jason P. Mitchell and Anthony D. Wagner},
  journal={Proceedings of the National Academy of Sciences of the United States of America},
  pages={2157 - 2162}
A central function of memory is to permit an organism to distinguish between stimuli that have been previously encountered and those that are novel. Although the medial temporal lobe (which includes the hippocampus and surrounding perirhinal, parahippocampal, and entorhinal cortices) is known to be crucial for recognition memory, controversy remains regarding how the specific subregions within the medial temporal lobe contribute to recognition. We used event-related functional MRI to examine… 

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Content-specific source encoding in the human medial temporal lobe.
  • T. Awipi, L. Davachi
  • Psychology, Biology
    Journal of experimental psychology. Learning, memory, and cognition
  • 2008
It was found that encoding activation in the right perirhinal cortex correlates with successful recollection of the paired object, and other MTL subregions also exhibited content-specific source encoding patterns of activation, suggesting that MTL subsequent memory effects are sensitive to stimulus category.
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.
Delay-dependent contributions of medial temporal lobe regions to episodic memory retrieval
The functional neuroimaging results suggest that the anterior and posterior hippocampus have different contributions to memory over time and that neurobiological models of memory must account for these differences.
Dissociable contributions within the medial temporal lobe to encoding of object-location associations.
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Selective and Shared Contributions of the Hippocampus and Perirhinal Cortex to Episodic Item and Associative Encoding
A subsequent memory paradigm that assessed successful item encoding in addition to the encoding of two distinct episodic details, providing strong evidence for a role of the hippocampus in domain-general associative encoding and raising the possibility that PrC encoding operations in conjunction with hippocampal mechanisms contribute to later recollection of presented item details.
Neural correlates of recognition memory for complex visual stimuli in the medial temporal lobe
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Contributions of medial temporal lobe and striatal memory systems to learning and retrieving overlapping spatial memories.
This study used functional magnetic resonance imaging in humans to test the prediction that the MTL and medial caudate play complementary roles in learning novel mazes that cross paths with, and must be distinguished from, previously learned routes and demonstrated parahippocampal cortex activity specific for novel spatial cues that distinguish between overlapping routes.
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.
Distinct roles for medial temporal lobe structures in memory for objects and their locations.
Using functional magnetic resonance imaging to determine whether the perirhinal and parahippocampal cortices show differential memory-related activity for spatial and object recognition memory supports the idea that MTL structures make distinct contributions to recognition memory performance.
Dissecting medial temporal lobe contributions to item and associative memory formation


Hippocampal contributions to episodic encoding: insights from relational and item-based learning.
Evidence is provided that the hippocampus, while engaged during item-based working memory maintenance, differentially subserves the relational binding of items into an integrated memory trace so that the experience can be later remembered.
Human declarative memory formation: Segregating rhinal and hippocampal contributions
The anatomically restricted interaction between word frequency and memory formation might indicate a semantically affected operation in the parahippocampal region supporting memory formation indirectly, and the missing interaction in hippocampal recordings might suggest a direct correlate of declarative memory formation that is insensitive to item properties.
Hippocampal, parahippocampal and occipital-temporal contributions to associative and item recognition memory: an fMRI study
The results indicate that partially distinct temporal lobe regions are involved during recognition memory for item and associative information.
Damage limited to the hippocampal region produces long-lasting memory impairment in monkeys
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This work focuses on the central issue in this dispute — the relative contributions of the hippocampus and the perirhinal cortex to recognition memory.
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How the cognitive and neural coding mechanisms that underlie declarative memory work together to create and re-create fully networked representations of previous experiences and knowledge about the world are described.
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It is argued that the perirhinal cortex, in particular, contributes to object identification in at least two ways: by serving as the final stage in the ventral visual cortical pathway that represents stimulus features, and by operating as part of a network for associating together sensory inputs within and across sensory modalities.
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Real-time tracking of memory formation in the human rhinal cortex and hippocampus.
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