Thalamic Stimulation Improves Postictal Cortical Arousal and Behavior

Area of Science:

• Neuroscience
• Epilepsy Research
• Neuromodulation

Background:

• The postictal state, following seizures, impairs consciousness and negatively impacts epilepsy patients.
• Previous research suggests deep brain stimulation (DBS) of the thalamic intralaminar central lateral nucleus (CL) may improve arousal levels in disorders of consciousness.

Purpose of the Study:

• To investigate the effects of postictal thalamic CL DBS on cortical electrophysiology and behavior in a rat model.
• To assess the potential of DBS as a therapeutic strategy for improving postictal responsiveness in epilepsy.

Main Methods:

• Electrical hippocampal stimulation induced secondarily generalized seizures in 21 female rats.
• Bilateral thalamic CL DBS (100 Hz) was applied during the postictal period.
• Cortical electrophysiology and behavioral performance on two tasks (licking, shock escape/avoidance) were measured.

Main Results:

• The postictal state exhibited frontal cortical slow waves and impaired behavioral responses.
• Thalamic CL DBS prevented postictal slow wave activity and significantly improved performance on the shock escape/avoidance task.
• Modest behavioral improvement was observed on a spontaneous licking task.

Conclusions:

• Thalamic CL DBS can decrease postictal cortical slow wave activity and enhance behavioral responsiveness.
• DBS of subcortical arousal structures presents a potential novel therapeutic strategy for medically and surgically refractory epilepsy.
• These preclinical findings support the foundation for human neurostimulation trials to improve postictal responsiveness.