The critical role of the inferior frontal cortex in establishing a prediction model for generating subsequent mismatch negativity (MMN): A TMS-EEG study

BackgroundThe prediction violation account of automatic or pre-attentive change detection assumed that the inferior frontal cortex (IFC) is involved in establishing a prediction model for detecting unexpected changes. Evidence supporting the IFC’s contribution to prediction model is mainly based on the Mismatch Negativity (MMN) to deviants violating predictions that are established based on the frequently presented standard events. However, deviant detection involves processes, such as events comparison, other than prediction model establishment.ObjectiveThe current study investigated the critical role of the IFC in establishing a prediction model during standards processing for subsequent deviant detection.MethodsTranscranial Magnetic Stimulation (TMS) was applied at the IFC to disrupt the processing of the initial 2 or 5 standards of a 3-, 6-, or 9-standard train, while the MMN responses to pitch deviant presented after the standard trains were recorded and compared.ResultsAn abolishment of MMN was only observed when TMS was delivered to the IFC at the initial 2 standards of the 3-standard train, but not at the initial 5 standards, or when TMS at the vertex or TMS sound recording was applied. The MMNs were also preserved when IFC TMS, vertex TMS, or TMS sound recording was applied at the initial 2 or 5 standards of longer trains.ConclusionThe IFC plays a critical role in processing the initial standards of a short standard train for subsequent deviant detection. This result is consistent with the prediction violation account that the IFC is important for establishing the prediction model.     

The Associations of Dietary Inflammatory Potential With Musculoskeletal Health in Chinese Community-Dwelling Older People: The Mr. OS and Ms. OS (Hong Kong) Cohort Study

Inflammation, an important contributory factor of muscle and bone aging, is potentially modulated by diet. This study examined the associations of dietary inflammatory index (DII) score with musculoskeletal parameters and related disease outcomes in 3995 community-dwelling Chinese men and women aged ≥65 years in Hong Kong. DII score at baseline was estimated from a food frequency questionnaire. Bone mineral density (BMD) and muscle mass estimated by dual-energy X-ray absorptiometry (DXA), hand grip strength, gait speed, and chair stand test were measured at baseline, year 4, and year 14. The associations of DII score with the longitudinal changes of musculoskeletal parameters, and incidence of osteoporosis, sarcopenia, and fractures were examined by using general linear model, multinomial logistic regression model, and Cox proportional hazards regression model, respectively. After multiple adjustments, each tertile increase in DII score in men was associated with 0.37 (95% confidence interval [CI], 0.10–0.64) kg loss in grip strength and 0.02 (95% CI, 0.01–0.03) m/s loss in gait speed over 4 years. In men, the highest tertile of DII was associated with a higher risk of incident fractures, with adjusted and competing death adjusted hazard ratio (HR) (95% CI) of 1.56 (1.14–2.14) and 1.40 (1.02–1.91), respectively. In women, DII score was not significantly associated with any muscle-related outcomes or incidence of fracture, but a significant association between higher DII score and risk of osteoporosis at year 14 was observed, with the highest tertile of DII score having adjusted odds ratio (OR) (95% CI) of 1.90 (1.03–3.52). In conclusion, pro-inflammatory diet consumption promoted loss of muscle strength and physical function, and increased risk of fractures in older Chinese men. Pro-inflammatory diets had no significant association with muscle related outcomes but increased the long-term risk of osteoporosis in older Chinese women. © 2022 American Society for Bone and Mineral Research (ASBMR).     

Beyond muscles: The untapped potential of creatine

Creatine is widely used by both elite and recreational athletes as an ergogenic aid to enhance anaerobic exercise performance. Older individuals also use creatine to prevent sarcopenia and, accordingly, may have therapeutic benefits for muscle wasting diseases. Although the effect of creatine on the musculoskeletal system has been extensively studied, less attention has been paid to its potential effects on other physiological systems. Because there is a significant pool of creatine in the brain, the utility of creatine supplementation has been examined in vitro as well as in vivo in both animal models of neurological disorders and in humans. While the data are preliminary, there is evidence to suggest that individuals with certain neurological conditions may benefit from exogenous creatine supplementation if treatment protocols can be optimized. A small number of studies that have examined the impact of creatine on the immune system have shown an alteration in soluble mediator production and the expression of molecules involved in recognizing infections, specifically toll-like receptors. Future investigations evaluating the total impact of creatine supplementation are required to better understand the benefits and risks of creatine use, particularly since there is increasing evidence that creatine may have a regulatory impact on the immune system.