Working memory (WM) representations serve as templates that guide behavior, but the neural basis of these templates remains elusive. We tested the hypothesis that WM templates are maintained by biasing activity in sensoriperceptual neurons that code for features of items being held in memory. Neural activity was recorded using event-related potentials (ERPs) as participants viewed a series of faces and responded when a face matched a target face held in WM. Our prediction was that if activity in neurons coding for the features of the target is preferentially weighted during maintenance of the target, then ERP activity evoked by a nontarget probe face should be commensurate with the visual similarity between target and probe. Visual similarity was operationalized as the degree of overlap in visual features between target and probe. A face-sensitive ERP response was modulated by target-probe similarity. Amplitude was largest for probes that were similar to the target, and decreased monotonically as a function of decreasing target-probe similarity. These results indicate that neural activity is weighted in favor of visual features that comprise an actively held memory representation. As such, our findings support the notion that WM templates rely on neural populations involved in forming percepts of memory items.
We have developed a low dose Mindfulness-Based Intervention (MBI-ld) that reduces the time committed to meetings and formal mindfulness practice, while conducting the sessions during the workday. This reduced the barriers commonly mentioned for non-participation in mindfulness programs. In a controlled randomized trial we studied university faculty and staff (n=186) who were found to have an elevated CRP level,>3.0 mg/ml, and who either had, or were at risk for cardiovascular disease. This study was designed to evaluate if MBI-ld could produce a greater decrease in CRP, IL-6 and cortisol than an active control group receiving a lifestyle education program when measured at the end of the 2 month interventions. We found that MBI-ld significantly enhanced mindfulness by 2-months and it was maintained for up to a year when compared to the education control. No significant changes were noted between interventions in cortisol, IL-6 levels or self-reported measures of perceived stress, depression and sleep quality at 2-months. Although not statistically significant (p=.08), the CRP level at 2-months was one mg/ml lower in the MBI-ld group than in the education control group, a change which may have clinical significance (Ridker et al., 2000; Wassel et al., 2010). A larger MBI-ld effect on CRP (as compared to control) occurred among participants who had a baseline BMI <30 (-2.67 mg/ml) than for those with BMI >30 (-0.18 mg/ml). We conclude that MBI-ld should be more fully investigated as a low-cost self-directed complementary strategy for decreasing inflammation, and it seems most promising for non-obese subjects.
BACKGROUND: Although yoga and meditation have been used for stress reduction with reported improvement in inflammation, little is known about the biological mechanisms mediating such effects. The present study examined if a yogic meditation might alter the activity of inflammatory and antiviral transcription control pathways that shape immune cell gene expression. METHODS: Forty-five family dementia caregivers were randomized to either Kirtan Kriya Meditation (KKM) or Relaxing Music (RM) listening for 12 min daily for 8 weeks and 39 caregivers completed the study. Genome-wide transcriptional profiles were collected from peripheral blood leukocytes sampled at baseline and 8-week follow-up. Promoter-based bioinformatics analyses tested the hypothesis that observed transcriptional alterations were structured by reduced activity of the pro-inflammatory nuclear factor (NF)-κB family of transcription factors and increased activity of Interferon Response Factors (IRFs; i.e., reversal of patterns previously linked to stress). RESULTS: In response to KKM treatment, 68 genes were found to be differentially expressed (19 up-regulated, 49 down-regulated) after adjusting for potentially confounded differences in sex, illness burden, and BMI. Up-regulated genes included immunoglobulin-related transcripts. Down-regulated transcripts included pro-inflammatory cytokines and activation-related immediate-early genes. Transcript origin analyses identified plasmacytoid dendritic cells and B lymphocytes as the primary cellular context of these transcriptional alterations (both p<.001). Promoter-based bioinformatic analysis implicated reduced NF-κB signaling and increased activity of IRF1 in structuring those effects (both p<.05). CONCLUSION: A brief daily yogic meditation intervention may reverse the pattern of increased NF-κB-related transcription of pro-inflammatory cytokines and decreased IRF1-related transcription of innate antiviral response genes previously observed in healthy individuals confronting a significant life stressor.