Thalamic organization differentially contributes to clinical conditions in epilepsy

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• The thalamus is implicated in temporal lobe epilepsy (TLE) but its role across various clinical conditions remains unclear.
• No prior studies have investigated if thalamic local and connectome properties influence patient status across diverse TLE conditions.

Purpose of the Study:

• To examine the association between thalamic local and connectome properties and clinical conditions in focal TLE.
• To differentiate the thalamus's role in pre- vs. post-surgical brain organization concerning seizure and neurocognitive outcomes.

Main Methods:

• Retrospective longitudinal MRI study including resting-state fMRI and structural imaging.
• Analyzed 91 TLE patients and 85 healthy controls across six binary clinical conditions.
• Identified whole-brain focal/regional and connectome-level features related to TLE.

Main Results:

• Thalamic features showed the strongest influence across all TLE conditions.
• Pre-surgical thalamic hyperconnectivity predicted poorer seizure control; post-surgical reorganization was not linked to seizure outcomes.
• Local ipsilateral thalamic properties correlated with neurocognitive outcomes, with pre-surgical organization linked to better cognitive preservation and post-surgical organization to decline.

Conclusions:

• Thalamic properties are robustly and recurrently associated with multiple TLE clinical conditions.
• The study distinguishes the thalamus's role in pre- vs. post-surgical organization regarding seizure and neuropsychological outcomes.
• Findings highlight the thalamus's importance for planning and prognosis in epilepsy surgery.