Working memory network plasticity after anterior temporal lobe resection: a longitudinal functional magnetic...

Area of Science:

• Neuroscience
• Cognitive Psychology
• Neurosurgery

Background:

• Working memory deficits are common in temporal lobe epilepsy (TLE).
• It remains unclear if TLE-related working memory impairment stems from temporal lobe dysfunction or extratemporal seizure spread.
• Anterior temporal lobe resection (ATLR) is a common treatment for drug-resistant TLE, but its effects on working memory are not well understood.

Purpose of the Study:

• To investigate the impact of ATLR on the efficiency and functional neuroanatomy of working memory networks in TLE patients.
• To correlate changes in brain activity with behavioral improvements in working memory post-surgery.

Main Methods:

• 33 TLE patients (16 left-sided) and 15 healthy controls underwent neuropsychological testing and fMRI for a visuospatial working memory task before and 3 and 12 months after ATLR.
• Analysis focused on changes in brain activation and deactivation patterns, with performance changes as a covariate.

Main Results:

• TLE patients showed preoperative working memory deficits. Performance improved post-ATLR, particularly after left-sided resections.
• Improved left ATLR outcomes correlated with hippocampal deactivation; right ATLR showed parietal lobe activation increases.
• Right hippocampal deactivation post-right ATLR was linked to lesser performance gains.

Conclusions:

• Working memory function can improve after ATLR in TLE patients.
• Postoperative working memory relies on the remaining hippocampal capacity and contralateral structures, especially after left ATLR.
• These findings highlight the role of posterior medial temporal lobes and eloquent cortex in working memory post-resection.