Hippocampus
Core of H.M.’s medial temporal resection story.
Darker cells mean a higher score for this topic on that metric.
Research80
Awareness55
Complexity60
Clinical weight50
Plasticity45
Live debate40
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Quick answers
Who was patient H.M. in Milner story?
Henry Molaison (1953 bilateral medial temporal surgery). He lost new episodic memory while retaining skills — the dissociation that remade memory science.
What year marks Scoville and Milner report?
1957. The paper tied hippocampal removal to anterograde amnesia without collapsing language or IQ in the teaching summary.
What did mirror-tracing show?
H.M. improved at mirror-tracing across days without remembering the sessions — procedural skill without episodic recall.
Is this a clinical guide to epilepsy surgery?
No. History of published cognitive neuroscience. Not medical advice, diagnosis, or surgical counsel.
Where did Milner work for decades?
Montreal Neurological Institute — careful testing, frontal-lobe work, and mentorship alongside the H.M. archive.
What atlas regions pair with her lesson?
Hippocampus (memory index) and frontal lobes (control). Use dual-view; do not invent a personal lesion map.
The anatomical lesson of Milner’s era is medial temporal: hippocampus and neighbouring cortex for declarative encoding — not the whole brain as a single memory store.
Later imaging refined which subregions matter; the original dissociation still anchors teaching maps.
Structures
Entorhinal / perirhinal cortex
Neighbour cortices also implicated in declarative memory.
Amygdala (partial in H.M.)
Resected tissue included amygdala; affective lessons are nuanced.
Frontal lobes
Milner’s wider programme on strategy and memory control.
Basal ganglia (skill learning)
Systems supporting procedural gains H.M. could show.
Neocortical remote stores
Where consolidated remote memories can survive MTL loss.
Pathways
Perforant / trisynaptic circuit
Classic hippocampal loop for encoding.
MTL–neocortical consolidation paths
Framework for why remote memories can remain.
Frontostriatal skill loops
Support procedural learning dissociated from episodes.
Fornix / diencephalic memory routes
Other amnesia anatomies that refine the MTL story.
Landmarks
Scoville resection diagrams
Historical surgical maps of H.M.’s lesion.
Mirror-tracing task
Iconic demonstration of intact skill learning.
Delayed recall batteries
Quantify anterograde declarative loss.
Post-mortem / MRI re-evaluations
Later anatomy refined what was actually removed.
Open atlas neighbours: hippocampus, entorhinal, amygdala, frontal.
Sources & research
- Loss of recent memory after bilateral hippocampal lesionsLandmark H.M. memory loss report.DOI
- The legacy of patient H.M. for neuroscienceLegacy review of patient H.M.DOI
- Cognitive neuroscience and the study of memoryCognitive neuroscience of memory synthesis.DOI
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