Coupling of Cortical and Thalamic Ictal Activity in Human Partial Epilepsy: Demonstration by Functional Magnetic Resonance Imaging

Summary: Purpose: To localize metabolic coupling between a cortical seizure focus and other brain regions by using functional magnetic resonance imaging (fMRI) data of ictal events obtained in a patient with frequent partial seizures involving his right face.
Methods: Cross-correlation analysis was used to examine time-dependent alterations in regional signal intensity that correlated with signal-intensity changes from a well-characterized cortical seizure focus in a patient with frequent partial seizures.
Results: Signal changes in the left ventrolateral thalamus showed a high degree of temporal correlation with signal changes in the left frontal cortical seizure focus, demonstrating close corticothalamic coupling of metabolism.
Conclusions: A significant role for thalamocortical interactions in the pathophysiology of epilepsy has been suggested by studies in animal models and human patients. This finding provides further support for the integral involvement of the thalamus in human focal epilepsy and underscores the potential for identifying neuronal networks by using cross-correlation analysis of fMRI data.