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Updated: Mar 11, 2026
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Investigations on Alterations of Hippocampal Circuit Function Following Mild Traumatic Brain Injury
Published on: November 19, 2012
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Hippocampal and diencephalic pathology in developmental amnesia.
Anna M Dzieciol1, Jocelyne Bachevalier2, Kadharbatcha S Saleem3
1University College London Great Ormond Street Institute of Child Health, London, UK.
Summary
Developmental amnesia (DA) involves hippocampal damage, but this study reveals significant atrophy in the mammillary bodies and thalamus. These diencephalic structures also contribute to memory deficits in DA patients.
Area of Science:
- Neuroscience
- Neuroimaging
- Cognitive Psychology
Background:
- Developmental amnesia (DA) is an episodic memory disorder linked to early-onset hippocampal atrophy from hypoxia.
- Brain damage in DA was thought to be confined to the hippocampus.
- The diencephalon, including the thalamus and mammillary bodies, is part of the hippocampal network and vulnerable to hypoxic injury.
Purpose of the Study:
- To investigate diencephalic damage in patients with developmental amnesia.
- To explore the role of diencephalic structures in the memory deficits associated with DA.
Main Methods:
- Neuroimaging investigation using MRI.
- Comparison of diencephalic volumes between 18 DA patients and 18 age-matched controls.
- Correlation analysis between thalamic segment size and visual memory performance.
Main Results:
- Significant mammillary body atrophy was observed in two-thirds of DA patients.
- DA patients, as a group, exhibited mildly reduced thalamic volumes.
- The size of the anterior-mid thalamic (AMT) segment correlated with visual memory performance.
Conclusions:
- Diencephalic structures, particularly the mammillary bodies and thalamus, are affected in developmental amnesia.
- These diencephalic regions play a role in the memory deficits characteristic of DA, beyond hippocampal involvement.
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