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Updated: Jul 2, 2026
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Assessment of Memory Function in Pilocarpine-induced Epileptic Mice
Published on: June 4, 2020
Dissociable roles for cortical and subcortical structures in memory retrieval and acquisition
Anna S Mitchell1, Philip G F Browning, Charles R E Wilson
1Department of Experimental Psychology, Oxford University, Oxford OX1 3UD, United Kingdom. nna.mitchell@psy.ox.ac.uk
Summary
Extensive subcortical damage impairs new learning and memory retention, causing retrograde amnesia. This contrasts with localized damage, highlighting the impact of widespread brain disruption on memory function.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Neurobiology
Background:
- The distinction between anterograde and retrograde amnesia is complex.
- Subcortical damage is often linked to greater anterograde amnesia, while cortical damage is linked to greater retrograde amnesia.
- Medial diencephalon damage in humans causes both types of amnesia, creating a need for reconciliation.
Purpose of the Study:
- To investigate the differential effects of subcortical versus cortical lesions on memory.
- To reconcile conflicting data on amnesia patterns following brain damage.
- To assess the impact of specific lesions on retention, relearning, and new learning.
Main Methods:
- Rhesus monkeys learned scene discriminations.
- Preoperative and postoperative one-trial retrieval tests assessed retention.
- Lesions were made to the magnocellular mediodorsal thalamus and fornix, or the entorhinal cortex.
Main Results:
- Combined subcortical lesions (mediodorsal thalamus and fornix) impaired retention, relearning, and new learning.
- Discrete lesions to single subcortical structures did not impair retention.
- Entorhinal cortex lesions impaired retention but not new learning.
- Widespread subcortical damage leading to cortical disruption caused retrograde amnesia.
Conclusions:
- Subcortical damage disproportionately affects new learning, while cortical damage disproportionately affects memory retention.
- Retrograde amnesia results from subcortical damage only when it is extensive and disrupts cortical function.
- These findings clarify the relationship between lesion location, extent, and amnesia type.
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