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Updated: Jun 3, 2026
Investigating Long-term Synaptic Plasticity in Interlamellar Hippocampus CA1 by Electrophysiological Field Recording
Published on: August 11, 2019
Hippocampal atrophy in temporal lobe epilepsy: the 'generator' and 'receiver'
L Bonilha1, J J Halford, P S Morgan
1Division of Neurology, Department of Neurosciences, Medical University of South Carolina, Charleston, 29425, USA. bonilha@musc.edu
Objective:
Some patients with unilateral medial temporal lobe epilepsy (MTLE) display bilateral hippocampal atrophy on MRI, even though seizures originate in only one hippocampus. The correct identification of the epileptogenic hippocampus (the 'generator') vs the non-epileptogenic (the 'receiver') may lead to better surgical planning and results.
Materials And Methods:
We studied 14 patients with MTLE (eight left and six right) who became seizure free after unilateral hippocampal resection, with hippocampal sclerosis confirmed by histology. Hippocampal tridimensional morphometry was performed comparing patients and healthy controls employing a voxel-wise Wilcoxon test. Results were corrected for multiple comparisons with the application of a False Discovery Rate (FDR)-corrected threshold for q < 0.05.
Results:
Patients with MTLE showed atrophy involving the ipsilateral hippocampus and the contralateral hippocampus, more pronouncedly within the ipsilateral hippocampus in the anterior-inferior aspect of the hippocampal head (left MTLE, left hippocampus x = -28, y = -16, z = -24, Z = 3.6; right MTLE, right hippocampus x = 22, y = -11, z = -27, Z = 2.9). On the contralateral hippocampus, the atrophy was more noticeable in the posterior head and body areas.
Conclusion:
The epileptogenic hippocampal atrophy has an anatomically distinct pattern compared with the contralateral hippocampus. This information may help guide the presurgical assessment of MTLE.
Insights
Patients with unilateral medial temporal lobe epilepsy (MTLE) show distinct patterns of hippocampal atrophy. Identifying the seizure-generating hippocampus is crucial for surgical planning in MTLE.
Area of Science:
- Neurology
- Neurosurgery
- Medical Imaging
Background:
- Unilateral medial temporal lobe epilepsy (MTLE) can present with bilateral hippocampal atrophy on MRI.
- Distinguishing the seizure-originating (generator) from the non-originating (receiver) hippocampus is vital for surgical success.
Purpose of the Study:
- To investigate the distinct patterns of hippocampal atrophy in patients with MTLE.
- To determine if atrophy patterns can differentiate the epileptogenic hippocampus from the non-epileptogenic one.
Main Methods:
- Studied 14 seizure-free MTLE patients post-unilateral hippocampal resection with confirmed hippocampal sclerosis.
- Performed 3D hippocampal morphometry comparing patients and controls using voxel-wise Wilcoxon tests.
- Applied False Discovery Rate (FDR) correction for multiple comparisons (q < 0.05).
Main Results:
- MTLE patients exhibited atrophy in both ipsilateral and contralateral hippocampi.
- Atrophy was more pronounced in the ipsilateral hippocampus, particularly the anterior-inferior head.
- Contralateral hippocampal atrophy was more evident in the posterior head and body areas.
Conclusions:
- Epileptogenic hippocampal atrophy displays a unique anatomical pattern compared to the contralateral side.
- These findings can aid in the presurgical assessment of MTLE patients.
- Differentiating hippocampal atrophy patterns may improve surgical planning and outcomes.
