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Updated: Jul 30, 2026
Multi-electrode Array Recordings of Human Epileptic Postoperative Cortical Tissue
Published on: October 26, 2014
Microdysgenesis with abnormal cortical myelinated fibres in temporal lobe epilepsy: a histopathological study with
M Thom1, J L Holton, C D'Arrigo
1Department of Neuropathology, Institute of Neurology, London, UK. MThom@ion.ucl.ac.uk
Abstract:
Microdysgenesis is a microscopic cortical malformation reported to occur with varying incidence in surgical lobectomies from patients with temporal lobe epilepsy (TLE). It may act as a substrate for the seizures. Four patients are reported with TLE, hippocampal sclerosis and cortical microdysgenesis which was also characterized by the presence of abnormal myelinated fibres running tangentially in the superficial cortical laminae and closely associated with abnormal clusters of neurones. Similar abnormal cortical fibres have been described in other malformations of cortical development including polymicrogyria and focal cortical dysplasia and it is therefore likely that these fibres represent part of the microdysgenetic malformation not hitherto reported. The possibility is discussed that they may also be of functional significance in terms of influencing local seizure propagation and the secondary cortical neuronal loss observed, predominantly affecting layer II. Studies of calbindin interneuronal populations showed preservation of these cells in the microdysgenetic cortex, when compared with non-malformed temporal lobes, despite an overall reduction in cortical neuronal density. In addition, prominent numbers of neurogliaform calbindin-positive nerve cells were observed in the microdysgenesis cases and the nature of these cells is speculated upon.
Insights
Microdysgenesis, a microscopic cortical malformation in temporal lobe epilepsy (TLE), involves abnormal myelinated fibers and neuronal clusters. These may contribute to seizure propagation and neuronal loss.
Area of Science:
- Neuroscience
- Neuropathology
- Epilepsy Research
Background:
- Microdysgenesis is a microscopic cortical malformation observed in temporal lobe epilepsy (TLE).
- It is hypothesized to be a potential substrate for seizures in TLE patients.
- The precise nature and implications of microdysgenesis require further elucidation.
Purpose of the Study:
- To characterize the neuropathological features of microdysgenesis in TLE patients.
- To investigate the association between microdysgenesis, abnormal myelinated fibers, and neuronal organization.
- To explore the potential functional significance of these malformations in seizure activity and neuronal loss.
Main Methods:
- Histopathological examination of surgical lobectomy specimens from four TLE patients.
- Microscopic analysis to identify cortical malformations, abnormal myelinated fibers, and neuronal clusters.
- Immunohistochemical studies, including calbindin staining, to assess interneuronal populations.
Main Results:
- The study identified microdysgenesis characterized by abnormal tangential myelinated fibers and clustered neurons in TLE patients.
- These abnormal fibers resemble those found in other cortical developmental malformations.
- Calbindin-positive interneurons were preserved in microdysgenetic cortex, with prominent neurogliaform calbindin-positive cells observed.
Conclusions:
- Abnormal myelinated fibers and neuronal clusters are integral features of microdysgenesis in TLE.
- These malformations may play a role in seizure propagation and secondary cortical neuronal loss.
- Preservation of certain interneurons and the presence of unique calbindin-positive cells warrant further investigation.
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