Effects of High-Intensity Interval Training Protocols on Blood Lactate Levels and Cognition in Healthy Adults: Systematic Review and Meta-Regression.

BACKGROUND: Some health benefits from high-intensity interval training (HIIT) are facilitated by peripheral blood lactate levels. However, the lactate response from HIIT is variable and dependent on protocol parameters. OBJECTIVES: We aimed to determine the HIIT protocol parameters that elicited peak lactate levels, and how these levels are associated with post-HIIT cognitive performance. STUDY DESIGN: We conducted a systematic review with meta-regression. METHODS: MEDLINE, Embase, CENTRAL, SPORTDiscus, and CINAHL + were searched from database inception to 8 April, 2022. Peer-reviewed primary research in healthy adults that determined lactate (mmol/L) and cognitive performance after one HIIT session was included. Mixed-effects meta-regressions determined the protocol parameters that elicited peak lactate levels, and linear regressions modelled the relationship between lactate levels and cognitive performance. RESULTS: Study entries (n = 226) involving 2560 participants (mean age 24.1 ± 4.7 years) were included in the meta-regression. A low total work-interval volume (~ 5 min), recovery intervals that are about five times longer than work intervals, and a medium session volume (~ 15 min), elicited peak lactate levels, even when controlling for intensity, fitness (peak oxygen consumption) and blood measurement methods. Lactate levels immediately post-HIIT explained 14-17% of variance in Stroop interference condition at 30 min post-HIIT. CONCLUSIONS: A HIIT protocol that uses the above parameters (e.g., 8 × 30-s maximal intensity with 90-s recovery) can elicit peak lactate, a molecule that is known to benefit the central nervous system and be involved in exercise training adaptations. This review reports the state of the science in regard to the lactate response following HIIT, which is relevant to those in the sports medicine field designing HIIT training programs. TRIAL REGISTRY: Clinical Trial Registration: PROSPERO (CRD42020204400).

Longitudinal Patterns of Functional Connectivity in Moderate-to-Severe Traumatic Brain Injury.

Longitudinal neuroimaging studies aid our understanding of recovery mechanisms in moderate-to-severe traumatic brain injury (TBI); however, there is a dearth of longitudinal functional connectivity research. Our aim was to characterize longitudinal functional connectivity patterns in two clinically important brain networks, the frontoparietal network (FPN) and the default mode network (DMN), in moderate-to-severe TBI. This inception cohort study of prospectively collected longitudinal data used resting-state functional magnetic resonance imaging (fMRI) to characterize functional connectivity patterns in the FPN and DMN. Forty adults with moderate-to-severe TBI (mean ± standard deviation [SD]; age = 39.53 ± 16.49 years, education = 13.92 ± 3.20 years, lowest Glasgow Coma Scale score = 6.63 ± 3.24, sex = 70% male) were scanned at approximately 0.5, 1-1.5, and 3+ years post-injury. Seventeen healthy, uninjured participants (mean ± SD; age = 38.91 ± 15.57 years, education = 15.11 ± 2.71 years, sex = 29% male) were scanned at baseline and approximately 11 months afterwards. Group independent component analyses and linear mixed-effects modeling with linear splines that contained a knot at 1.5 years post-injury were employed to investigate longitudinal network changes, and associations with covariates, including age, sex, and injury severity. In patients with TBI, functional connectivity in the right FPN increased from approximately 0.5 to 1.5 years post-injury (unstandardized estimate = 0.19, standard error [SE] = 0.07, p = 0.009), contained a slope change in the opposite direction, from positive to negative at 1.5 years post-injury (estimate = -0.21, SE = 0.11, p = 0.009), and marginally declined afterwards (estimate = -0.10, SE = 0.06, p = 0.079). Functional connectivity in the DMN increased from approximately 0.5 to 1.5 years (estimate = 0.15, SE = 0.05, p = 0.006), contained a slope change in the opposite direction, from positive to negative at 1.5 years post-injury (estimate = -0.19, SE = 0.08, p = 0.021), and was estimated to decline from 1.5 to 3+ years (estimate = -0.04, SE = 0.04, p = 0.303). Similarly, the left FPN increased in functional connectivity from approximately 0.5 to 1.5 years post-injury (estimate = 0.15, SE = 0.05, p = 0.002), contained a slope change in the opposite direction, from positive to negative at 1.5 years post-injury (estimate = -0.18, SE = 0.07, p = 0.008), and was estimated to decline thereafter (estimate = -0.04, SE = 0.03, p = 0.254). At approximately 0.5 years post-injury, patients showed hypoconnectivity compared with healthy, uninjured participants at baseline. Covariates were not significantly associated in any of the models. Findings of early improvement but a tapering and possible decline in connectivity thereafter suggest that compensatory effects are time-limited. These later reductions in connectivity mirror growing evidence of behavioral and structural decline in chronic moderate-to-severe TBI. Targeting such declines represents a novel avenue of research and offers potential for improving clinical outcomes.

Delusions of love and passion in the behavioral variant of frontotemporal dementia.

Erotomania (de Clérambault's syndrome) refers to the delusional belief that another person, usually socially unreachable, is in love with the holder of the delusion. The occurrence of erotomania in Frontotemporal Dementia has rarely been reported. We present the unique case of a 59-year-old woman with a strong family history of early-onset dementia in whom erotomania was the initial manifestation that led to a diagnosis of definite Behavioral Variant of Frontotemporal Dementia with a pathogenic missense mutation in the MAPT gene. Based on this case, we propose a hypothetical model for developing erotomania in patients with FTD.

Effects of high-intensity interval training on blood lactate levels and cognition in healthy adults: protocol for systematic review and network meta-analyses.

BACKGROUND: High-intensity interval training (HIIT) has shown to confer cognitive benefits in healthy adults, via a mechanism purportedly driven by the exercise metabolite lactate. However, our understanding of the exercise parameters (e.g., work interval duration, session volume, work-to-rest ratio) that evoke a peak blood lactate response in healthy adults is limited. Moreover, evidence relating HIIT-induced blood lactate and cognitive performance has yet to be reviewed and analyzed. The primary objective of this systematic review is to use network meta-analyses to compare the relative impact of different HIIT work-interval durations, session volumes, and work-to-rest ratios on post-exercise blood lactate response in healthy adults. The secondary objective is to determine the relationship between HIIT-induced blood lactate and acute post-HIIT cognitive performance. METHODS: A systematic review is being conducted to identify studies measuring blood lactate response following one session of HIIT in healthy adults. The search was carried out in (1) MEDLINE, (2) EMBASE, (3) Cochrane Central Register of Controlled Trials, (4) Sport Discus, and (5) Cumulative Index to Nursing and Allied Health Literature Plus with Full Text (CINAHL+). After abstract and full-text screening, two reviewers will independently extract data on key outcomes variables and complete risk of bias assessment using the Cochrane Risk of Bias Tool and the Risk of Bias in Non-Randomized Studies of Interventions tool. Network meta-analyses will be used to generate estimates of the comparative effectiveness of blood lactate on cognitive outcomes using corresponding rankings for each work-interval duration, session volume, and work-to-rest ratio category. Where applicable, meta-regressions analyses will be performed to test the relationship between changes in the blood lactate and changes in cognitive performance. Analyses will be conducted using MetaInsight Software. DISCUSSION: This study will provide evidence on how to structure a HIIT protocol to elicit peak blood lactate response in healthy adults and will increase our understanding of the relationship between HIIT-induced blood lactate response and associated cognitive benefits. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020204400.

The recycling endosome protein Rab25 coordinates collective cell movements in the zebrafish surface epithelium.

In emerging epithelial tissues, cells undergo dramatic rearrangements to promote tissue shape changes. Dividing cells remain interconnected via transient cytokinetic bridges. Bridges are cleaved during abscission and currently, the consequences of disrupting abscission in developing epithelia are not well understood. We show that the Rab GTPase Rab25 localizes near cytokinetic midbodies and likely coordinates abscission through endomembrane trafficking in the epithelium of the zebrafish gastrula during epiboly. In maternal-zygotic Rab25a and Rab25b mutant embryos, morphogenic activity tears open persistent apical cytokinetic bridges that failed to undergo timely abscission. Cytokinesis defects result in anisotropic cell morphologies that are associated with a reduction of contractile actomyosin networks. This slows cell rearrangements and alters the viscoelastic responses of the tissue, all of which likely contribute to delayed epiboly. We present a model in which Rab25 trafficking coordinates cytokinetic bridge abscission and cortical actin density, impacting local cell shape changes and tissue-scale forces.