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Supplemental material, sj-docx-1-pss-10.1177_09567976211061107 for Resting (Tonic) Blood Pressure Is Associated With Sensitivity to Imagined and Acute Experiences of Social Pain: Evidence From Three Studies by Tristen K. Inagaki and Peter J. Gianaros in Psychological Science

Supplemental material, sj-pptx-1-pss-10.1177_0956797621989730 for Functional MRI Can Be Highly Reliable, but It Depends on What You Measure: A Commentary on Elliott et al. (2020) by Philip A. Kragel, Xiaochun Han, Thomas E. Kraynak, Peter J. Gianaros and Tor D. Wager in Psychological Science

BACKGROUND: Mindfulness meditation training interventions have been shown to improve markers of health, but the underlying neurobiological mechanisms are not known. Building on initial cross-sectional research showing that mindfulness meditation may increase default mode network (DMN) resting-state functional connectivity (rsFC) with regions important in top-down executive control (dorsolateral prefrontal cortex [dlPFC]), here we test whether mindfulness meditation training increases DMN-dlPFC rsFC and whether these rsFC alterations prospectively explain improvements in interleukin (IL)-6 in a randomized controlled trial. METHODS: Stressed job-seeking unemployed community adults (n = 35) were randomized to either a 3-day intensive residential mindfulness meditation or relaxation training program. Participants completed a 5-minute resting-state scan before and after the intervention program. Participants also provided blood samples at preintervention and at 4-month follow-up, which were assayed for circulating IL-6, a biomarker of systemic inflammation. RESULTS: We tested for alterations in DMN rsFC using a posterior cingulate cortex seed-based analysis and found that mindfulness meditation training, and not relaxation training, increased posterior cingulate cortex rsFC with left dlPFC (p < .05, corrected). These pretraining to posttraining alterations in posterior cingulate cortex-dlPFC rsFC statistically mediated mindfulness meditation training improvements in IL-6 at 4-month follow-up. Specifically, these alterations in rsFC statistically explained 30% of the overall mindfulness meditation training effects on IL-6 at follow-up. CONCLUSIONS: These findings provide the first evidence that mindfulness meditation training functionally couples the DMN with a region known to be important in top-down executive control at rest (left dlPFC), which, in turn, is associated with improvements in a marker of inflammatory disease risk.

We aimed to investigate if trajectory components (baseline level, slope, and variability) of peripheral interleukin-6 (IL-6) over time were related to cognitive impairment and smaller hippocampal volume and if hippocampal volume explained the associations between IL-6 and cognitive impairment. Multivariable regression models were used to test the association between IL-6 trajectory components with change in neuroimaging measures of the hippocampus and with cognitive impairment among 135 older adults (70-79years at baseline) from the Healthy Brain Project over 14years. IL-6 variability was positively associated with cognitive impairment (odds ratio [OR]= 5.86, 95% confidence interval [CI]: 1.24, 27.61) and with greater decrease per year of gray matter volume of the hippocampus (β=-0.008, standard error= 0.004, p= 0.03). After adjustment for hippocampal volume, the OR of cognitive impairment decreased for each unit of IL-6 variability and CIs widened (OR= 4.36, 95% CI: 0.67, 28.29). Neither baseline levels nor slopes of IL-6 were related to cognitive impairment or hippocampal volume. We believe this has potential clinical and public health implications by suggesting adults with stable levels of peripheral IL-6 may be better targets for intervention studies for slowing or preventing cognitive decline.

Being overweight or obese is associated with reduced white matter integrity throughout the brain. It is not yet clear which physiological systems mediate the association between inter-individual variation in adiposity and white matter. We tested whether composite indicators of cardiovascular, lipid, glucose, and inflammatory factors would mediate the adiposity-related variation in white matter microstructure, measured with diffusion tensor imaging on a group of neurologically healthy adults (N=155). A composite factor representing adiposity (comprised of body mass index and waist circumference) was associated with smaller fractional anisotropy and greater radial diffusivity throughout the brain, a pattern previously linked to myelin structure changes in non-human animal models. A similar global negative association was found for factors representing inflammation and, to a lesser extent, glucose regulation. In contrast, factors for blood pressure and dyslipidemia had positive associations with white matter in isolated brain regions. Taken together, these competing influences on the diffusion signal were significant mediators linking adiposity to white matter and explained up to fifty-percent of the adiposity-white matter variance. These results provide the first evidence for contrasting physiological pathways, a globally distributed immunity-linked negative component and a more localized vascular-linked positive component, that associate adiposity to individual differences in the microstructure of white matter tracts in otherwise healthy adults.

Insulin resistance confers risk for diabetes mellitus and associates with a reduced capacity of the arterial baroreflex to regulate blood pressure. Importantly, several brain regions that comprise the central autonomic network, which controls the baroreflex, are also sensitive to the neuromodulatory effects of insulin. However, it is unknown whether peripheral insulin resistance relates to activity within central autonomic network regions, which may in turn relate to reduced baroreflex regulation. Accordingly, we tested whether resting cerebral blood flow within central autonomic regions statistically mediated the relationship between insulin resistance and an indirect indicator of baroreflex regulation; namely, baroreflex sensitivity. Subjects were 92 community-dwelling adults free of confounding medical illnesses (48 men, 30-50 years old) who completed protocols to assess fasting insulin and glucose levels, resting baroreflex sensitivity, and resting cerebral blood flow. Baroreflex sensitivity was quantified by measuring the magnitude of spontaneous and sequential associations between beat-by-beat systolic blood pressure and heart rate changes. Individuals with greater insulin resistance, as measured by the homeostatic model assessment, exhibited reduced baroreflex sensitivity (b = -0.16, p < .05). Moreover, the relationship between insulin resistance and baroreflex sensitivity was statistically mediated by cerebral blood flow in central autonomic regions, including the insula and cingulate cortex (mediation coefficients < -0.06, p-values < .01). Activity within the central autonomic network may link insulin resistance to reduced baroreflex sensitivity. Our observations may help to characterize the neural pathways by which insulin resistance, and possibly diabetes mellitus, relates to adverse cardiovascular outcomes.

Insulin resistance confers risk for diabetes mellitus and associates with a reduced capacity of the arterial baroreflex to regulate blood pressure. Importantly, several brain regions that comprise the central autonomic network, which controls the baroreflex, are also sensitive to the neuromodulatory effects of insulin. However, it is unknown whether peripheral insulin resistance relates to activity within central autonomic network regions, which may in turn relate to reduced baroreflex regulation. Accordingly, we tested whether resting cerebral blood flow within central autonomic regions statistically mediated the relationship between insulin resistance and an indirect indicator of baroreflex regulation; namely, baroreflex sensitivity. Subjects were 92 community-dwelling adults free of confounding medical illnesses (48 men, 30-50 years old) who completed protocols to assess fasting insulin and glucose levels, resting baroreflex sensitivity, and resting cerebral blood flow. Baroreflex sensitivity was quantified by measuring the magnitude of spontaneous and sequential associations between beat-by-beat systolic blood pressure and heart rate changes. Individuals with greater insulin resistance, as measured by the homeostatic model assessment, exhibited reduced baroreflex sensitivity (b = -0.16, p < .05). Moreover, the relationship between insulin resistance and baroreflex sensitivity was statistically mediated by cerebral blood flow in central autonomic regions, including the insula and cingulate cortex (mediation coefficients < -0.06, p-values < .01). Activity within the central autonomic network may link insulin resistance to reduced baroreflex sensitivity. Our observations may help to characterize the neural pathways by which insulin resistance, and possibly diabetes mellitus, relates to adverse cardiovascular outcomes.

The Motion Sickness Assessment Questionnaire (MSAQ) was developed in order to assess the multiple dimensions of the motion sickness syndrome (gastrointestinal, central nervous system, peripheral, and sopite-related symptoms). The aim of this study was to evaluate the psychometric properties of the Greek version of the MSAQ.The MSAQ was translated into Greek and then translated back into English. Minor differences between the two texts were corrected. The Greek version was then administered to male subjects before and after nauseogenic motion stimulation. With the use of a motor driven rotating chair, the subjects were exposed to Coriolis cross-coupling stimulation. A battery of statistical tests was used to evaluate the psychometric properties of the MSAQ.There were 112 subjects who participated. Internal consistency, measured with Cronbach's alpha coefficient, was excellent for the total scale and subscales. The test-retest evaluation was done with Pearson's coefficient and Bland-Altman's plot for the total score and subscales and showed statistically significant results. Mean total MSAQ score was 19.04 before the exposure and 33.46 after the exposure, which was statistically significant.Results suggest the Greek-MSAQ is a valid instrument with satisfactory internal consistency, reliability, reproducibility, validity, and responsiveness and can be used in future studies of motion sickness in Greek speaking populations. Kousoulis P, Pantes A, Alevetsovitis G, Fydanaki O. Psychometric properties of the Greek version of the Gianaros Motion Sickness Assessment Questionaire. Aerosp Med Hum Perform. 2016; 87(11):954-957.