Thalamo-cortical network dysfunction in temporal lobe epilepsy

Objectives Imaging and neurophysiological data shows that the cortical disfunction caused by focal epilepsy is not limited to the epileptic focus, thus raising the modern vision of focal epilepsy as a network disorder. The involvement of deep thalamo-cortical projections in temporal lobe epilepsy is a clear example. We aimed at demonstrating the interictal functional impairment of thalamo-cortical network in drug-naive TLE patients through the study of high frequency oscillations of somatosensory evoked potentials (HF-SEP). Methods Twelve healthy controls (HC; 8 females, 52.2 ± 17.3 years-old) and 12 drug-naive TLE patients (8 females, 55.5 ± 21.5 years-old) underwent bilateral median HF-SEP, recorded by scalp electrodes. Cp3′-Fz and Cp4′-Fz traces were filtered (400–800 Hz) to evidence HF-SEP. Results HF-SEP duration in the affected hemisphere was significantly longer when compared to that of both the unaffected hemisphere and HC hemispheres. No significant inter-hemispheric differences were found in areas, powers and latencies of HF-SEP wavelets. Conclusion Our results demonstrate that TLE induces early interictal functional impairments of the thalamo-cortical network. Significance Our data strongly corroborates the vision of focal epilepsy as a network disorder and offers a new neurophysiological tool to test pharmacological, surgical and neuromodulatory therapies.