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Altered microstructural connectivity in juvenile myoclonic epilepsy: the missing link.
C Vollmar1, J O'Muircheartaigh, M R Symms
1Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.
Neurology
|May 4, 2012
Summary
Juvenile myoclonic epilepsy (JME) involves abnormal brain connectivity, particularly in the mesial frontal lobe. These changes may explain how cognitive stressors trigger seizures in JME patients.
Area of Science:
- Neuroscience
- Epilepsy Research
- Brain Imaging
Background:
- Juvenile myoclonic epilepsy (JME) presents with myoclonic jerks often triggered by cognitive factors.
- JME is associated with a frontal lobe neuropsychological profile, photosensitivity, and motor cortex hyperexcitability.
- Advanced imaging has revealed abnormal functional connectivity in the motor cortex and supplementary motor area (SMA) in JME.
Purpose of the Study:
- To investigate the structural and functional connectivity of the mesial frontal lobe in JME patients.
- To correlate neuroimaging findings with the clinical characteristics of JME.
- To explore the neuroanatomical basis for cognitive triggering of seizures in JME.
Main Methods:
- Functional MRI (fMRI) and diffusion tensor imaging (DTI) were used in 29 JME patients and 28 controls.
- fMRI assessed functional connectivity, while DTI evaluated structural connectivity of the mesial frontal lobe.
- Region parcellation and voxel-wise comparison of tractography data were employed.
Main Results:
- JME patients exhibited altered mesial frontal connectivity, with increased structural connectivity between the prefrontal cortex and motor cortex.
- A positive correlation was observed between structural and functional connectivity measures.
- Reduced connectivity was found between prefrontal and frontopolar regions, and increased connectivity between the occipital cortex and SMA.
Conclusions:
- Alterations in mesial frontal microstructural connectivity may underlie the cognitive triggering of motor seizures in JME.
- These connectivity changes offer an explanatory framework for various JME clinical observations.
- The findings link seizure semiology, neurophysiology, neuropsychology, and imaging in JME.
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