Browsing by Subject "working memory"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    Differential Effects of Pergolide and Bromocriptine on Working Memory Performance and Brain Activation after Mild Traumatic Brain Injury
    (Liebert, 2020) Flashman, Laura A.; McDonald, Brenna C.; Ford, James C.; Kenny, Rachel M.; Andrews, Katharine D.; Saykin, Andrew J.; McAllister, Thomas W.; Radiology and Imaging Sciences, School of Medicine
    Dopamine D1 and D2 receptors differ with respect to patterns of regional brain distribution and behavioral effects. Pre-clinical work suggests that D1 agonists enhance working memory, but the absence of selective D1 agonists has constrained using this approach in humans. This study examines working memory performance in mild traumatic brain injury (mTBI) patients when given pergolide, a mixed D1/D2 agonist, compared with bromocriptine, a selective D2 agonist. Fifteen individuals were studied 1 month after mTBI and compared with 17 healthy controls. At separate visits, participants were administered 1.25 mg bromocriptine or 0.05 mg pergolide prior to functional magnetic resonance imaging (MRI) using a working memory task (visual-verbal n-back). Results indicated a significant group-by-drug interaction for mean performance across n-back task conditions, where the mTBI group showed better performance on pergolide relative to bromocriptine, whereas controls showed the opposite pattern. There was also a significant effect of diagnosis, where mTBI patients performed worse than controls, particularly while on bromocriptine, as shown in our prior work. Functional MRI activation during the most challenging task condition (3-back > 0-back contrast) showed a significant group-by-drug interaction, with the mTBI group showing increased activation relative to controls in working memory circuitry while on pergolide, including in the left inferior frontal gyrus. Across participants there was a positive correlation between change in activation in this region and change in performance between drug conditions. Results suggest that activation of the D1 receptor may improve working memory performance after mTBI. This has implications for the development of pharmacological strategies to treat cognitive deficits after mTBI.
  • Thumbnail Image
    Item
    Increased brain activation during working memory processing after pediatric mild traumatic brain injury (mTBI).
    (IOS Press, 2015) Westfall, Daniel R.; West, John D.; Bailey, Jessica N.; Arnold, Todd W.; Kersey, Patrick A.; Saykin, Andrew J.; McDonald, Brenna C.; Department of Radiology and Imaging Sciences, IU School of Medicine
    Purpose: The neural substrate of post-concussive symptoms following the initial injury period after mild traumatic brain injury (mTBI) in pediatric populations remains poorly elucidated. This study examined neuropsychological, behavioral, and brain functioning in adolescents post-mTBI to assess whether persistent differences were detectable up to a year post-injury. Methods: Nineteen adolescents (mean age 14.7 years) who experienced mTBI 3–12 months previously (mean 7.5 months) and 19 matched healthy controls (mean age 14.0 years) completed neuropsychological testing and an fMRI auditory-verbal N-back working memory task. Parents completed behavioral ratings. Results: No between-group differences were found for cognition, behavior, or N-back task performance, though the expected decreased accuracy and increased reaction time as task difficulty increased were apparent. However, the mTBI group showed significantly greater brain activation than controls during the most difficult working memory task condition. Conclusion: Greater working memory task-related activation was found in adolescents up to one year post-mTBI relative to controls, potentially indicating compensatory activation to support normal task performance. Differences in brain activation in the mTBI group so long after injury may indicate residual alterations in brain function much later than would be expected based on the typical pattern of natural recovery, which could have important clinical implications.
  • Thumbnail Image
    Item
    Involvement of the left anterior insula and frontopolar gyrus in odor discrimination
    (Wiley, 2006-11-06) Plailly, Jane; Radnovich, Alexander J.; Sabri, Merav; Royet, Jean-Pierre; Kareken, David A.; Neurology, School of Medicine
    Discriminating between successively presented odors requires brief storage of the first odor's perceptual trace, which then needs to be subsequently compared to the second odor in the pair. This study explores the cortical areas involved in odor discrimination and compares them with findings from studies of working‐memory, traditionally investigated with n‐back paradigms. Sixteen right‐handed subjects underwent H2 15O positron emission tomography during counterbalanced conditions of odorless sniffing, repeated single odor detection, multiple odor detection, and conscious successive discrimination between odor pairs. Eight odorants were delivered using a computer‐controlled olfactometer through a birhinal nasal cannula. Conscious successive odor discrimination evoked significantly greater activity in the left anterior insula and frontopolar gyrus when compared to reported sensory detection of the identical odors. Additional activation was found in the left lateral orbital/inferior frontal and middle frontal gyri when discrimination was compared to the odorless condition. The left anterior insula is likely involved in the evaluation of odor properties. Consistent with other studies, frontopolar and middle frontal gyrus activation is more likely related to working memory during odor discrimination.
  • Thumbnail Image
    Item
    Pain Catastrophizing Mediates and Moderates the Link Between Acute Pain and Working Memory
    (Elsevier, 2021-08) Procento, Philip M.; Rand, Kevin L.; Stewart, Jesse C.; Hirsh, Adam T.; Psychology, School of Science
    The bidirectional relationship between pain and working memory (WM) deficits is well-documented but poorly understood. Pain catastrophizing—exaggerated, negative cognitive and emotional responses toward pain—may contribute to WM deficits by occupying finite, shared cognitive resources. The present study assessed the role of pain catastrophizing as both a state-level process and trait-level disposition in the link between acute pain and WM. Healthy, young adults were randomized to an experimentally-induced ischemic pain or control task, during which they completed verbal and non-verbal WM tests. Participants also completed measures of state- and trait-level pain catastrophizing. Simple mediation analyses indicated that participants in the pain group (vs. control) engaged in more state-level catastrophizing about pain, which led to worse verbal and non-verbal WM. Moderated mediation analyses indicated that the indirect (mediation) effect of state-level pain catastrophizing was moderated by trait-level pain catastrophizing for both verbal and non-verbal WM. Participants in the pain group who reported a greater trait-level tendency to catastrophize about pain experienced greater state-level catastrophizing about pain during the ischemic task, which led to worse verbal and non-verbal WM performance. These results provide evidence for pain catastrophizing as an important mechanism and moderating factor of WM deficits in acute pain. Future research should replicate these results in chronic pain samples, investigate other potential mechanisms (e.g., sleep disturbances), and determine if interventions that target pain catastrophizing directly can ameliorate cognitive deficits in people with pain. Perspective This article presents a laboratory study examining the relationships among pain, pain catastrophizing, and working memory in healthy participants. The results shed new light on these relationships and raise the possibility that interventions that reduce catastrophizing may lead to improved cognitive function among people with pain.