[show abstract][hide abstract] ABSTRACT: Functional neuroimaging studies in healthy adults demonstrate involvement of a left-lateralized network of frontal, temporal, and parietal regions during a variety of semantic processing tasks. While these areas are believed to be fundamental to semantic processing, it is unclear if task performance is correlated with differential recruitment of these or other brain regions. The objective of this study was to identify the structures underlying improved accuracy on a semantic decision task. We also investigated whether extra-scanner performance on the Boston Naming Test (BNT) and Semantic Fluency Test (SFT), neuropsychological measures of semantic retrieval, is correlated with specific areas of activation during the semantic decision/tone decision (SDTD) fMRI task. Fifty-two healthy, right-handed individuals performed a block-design SDTD task. Regression analyses revealed that increased performance on this task was associated with activation in the right inferior parietal lobule. Higher SFT performance resulted in greater recruitment of right frontal regions; improved performance on BNT was associated with more widespread activation in prefrontal, temporal, and parietal cortex bilaterally, although this activation appeared to be stronger in the right hemisphere. Overall, our results suggest that improved performance on both intra- and extra-scanner measures of semantic processing are associated with increased recruitment of right hemispheric regions.
Brain research 09/2011; 1419:105-16. · 2.46 Impact Factor
[show abstract][hide abstract] ABSTRACT: Stress is a commonly reported seizure precipitant among individuals with epilepsy. Yet, the relationship between stress and seizure susceptibility remains unclear. This study examined the relationship between emotional distress and lifetime seizure load in individuals with temporal lobe epilepsy (TLE), as well as the potential moderating effect of explanatory style on this relationship. Data were collected from 148 individuals with TLE. Scales 2 and 7 of the Minnesota Multiphasic Personality Inventory were used as a measure of emotional distress, and explanatory style was measured using the Revised Optimism-Pessimism Scale. Elevated Scale 2 scores were associated with an increase in seizure load only in subjects with Full Scale IQ scores> or =92. An interaction between emotional distress and explanatory style was not observed. Thus, for individuals with higher levels of intelligence, depression may be an important pathway in linking emotional distress to poor seizure control.