Neural correlates of morphological decomposition in a morphologically rich language: an fMRI study

By employing visual lexical decision and functional MRI, we studied the neural correlates of morphological decomposition in a highly inflected language (Finnish) where most inflected noun forms elicit a consistent processing cost during word recognition. This behavioral effect could reflect suffix stripping at the visual word form level and/or subsequent meaning integration at the semantic-syntactic level. The first alternative predicts increased activation for inflected vs. monomorphemic words in the left occipitotemporal cortex while the second alternative predicts left inferior frontal gyrus and/or left posterior temporal activation increases. The results show significant activation effects in the latter areas. This provides support for the second alternative, i.e., that the morphological processing cost stems from the semantic-syntactic level.     

Sleep,resilience, and psychological distress in United States military Veterans

Sleep problems are prevalent among Veterans. Left untreated, such problems may elevate psychological distress and increase risk of subsequent mental health disorders. Psychological resilience may buffer against negative psychological outcomes, yet the relationship between sleep and resilience has not been studied. This study explored poor sleep, resilience, and psychological distress using questionnaires collected as part of the Study of Post-Deployment Mental Health. Participants (N = 1,118) had served in the US military since September 11, 2001, had one or more overseas deployments, and were free from a past-month DSM-defined mental health disorder. Hierarchical linear regression was used to examine the association between poor sleep quality (Pittsburgh Sleep Quality Index total score) and psychological distress (Global Symptom Index; Symptom Checklist-90-R), controlling for demographic and health characteristics. Moderation analyses tested for a potential buffering effect of resilience (Connor-Davidson Resilience Scale). Poor sleeping Veterans had worse physical and psychological health, lower resilience, and endorsed more lifetime traumatic events. Poor sleep was associated with greater psychological distress controlling for health and demographic characteristics. Both resilience factors—adaptability and self-efficacy—had significant buffering effects on the relationship between poor sleep and psychological distress, suggesting that resilience may protect against negative outcomes in poor sleepers. Additional research is warranted to better understand the relationships between sleep, resilience, and psychological distress. Such research may inform pertinent prevention efforts, including interventions that improve sleep, enhance resilience, and protect against incident mental health diagnoses.     

Central executive function in mild cognitive impairment: a PET activation study

Using positron emission tomography (PET), we explored the neural correlates of an executive function, dual tasking, in patients with amnestic mild cognitive impairment (aMCI) and in elderly controls. The experiment employed simple auditory and visual tasks that were presented both in isolation and simultaneously to create a task condition requiring enhanced attentional control. Behaviorally, both groups performed well, albeit the patients made more errors on the visual task. The PET analysis focused at prefrontal regions where group differences in task-related activation patterns were expected. During dual task performance, the patients showed attenuated activity in the left inferior frontal region when compared to the controls. This suggests abnormalities in the neural processes underlying attentional control in aMCI.