Decision making under ambiguity in temporal lobe epilepsy: does the location of the underlying structural abnormality matter?

Previous studies have reported decision-making deficits in patients affected by mesial temporal lobe epilepsy (TLE). The aim of the study described here was to assess the specificity of these deficits by comparing performance of patients with neocortical TLE, patients with mesial TLE, and healthy controls. The mesial TLE group performed lower than healthy controls and the neocortical TLE group in decision making under initial ambiguity. Although patients with neocortical TLE and controls showed a significant learning effect over the blocks of the Iowa gambling task, performance of patients with mesial TLE did not improve from the first to the last block of trials. Results suggest that TLE associated with neocortical brain abnormalities does not have deleterious effects on decision making as is found for epilepsy caused by mesial temporal lobe pathologies. The present findings highlight the specificity of the mesial temporal lobes in reward-based, adaptive learning and decision making.