RESUMO
When does the mind begin? Infant psychology is mysterious in part because we cannot remember our first months of life, nor can we directly communicate with infants. Even more speculative is the possibility of mental life prior to birth. The question of when consciousness, or subjective experience, begins in human development thus remains incompletely answered, though boundaries can be set using current knowledge from developmental neurobiology and recent investigations of the perinatal brain. Here, we offer our perspective on how the development of a sensory perturbational complexity index (sPCI) based on auditory ("beep-and-zip"), visual ("flash-and-zip"), or even olfactory ("sniff-and-zip") cortical perturbations in place of electromagnetic perturbations ("zap-and-zip") might be used to address this question. First, we discuss recent studies of perinatal cognition and consciousness using techniques such as functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and, in particular, magnetoencephalography (MEG). While newborn infants are the archetypal subjects for studying early human development, researchers may also benefit from fetal studies, as the womb is, in many respects, a more controlled environment than the cradle. The earliest possible timepoint when subjective experience might begin is likely the establishment of thalamocortical connectivity at 26 weeks gestation, as the thalamocortical system is necessary for consciousness according to most theoretical frameworks. To infer at what age and in which behavioral states consciousness might emerge following the initiation of thalamocortical pathways, we advocate for the development of the sPCI and similar techniques, based on EEG, MEG, and fMRI, to estimate the perinatal brain's state of consciousness.
Assuntos
Encéfalo , Estado de Consciência , Lactente , Criança , Recém-Nascido , Gravidez , Feminino , Humanos , Cognição , Magnetoencefalografia , Eletroencefalografia/métodosRESUMO
Sarcopenia and frailty are age-related syndromes with negative effects on the quality of life of older people and on public health costs. Although extensive research has been carried out on the effects of physical exercise and physical syndromes, there is a knowledge gap when it comes to the effect of resistance training on muscular strength, physical performance, and body composition at early (prevention) and late (treatment) stages in both syndromes combined. We conducted this systematic review and meta-analysis (CRD42019138253) to gather the evidence of randomized controlled trials examining the effects of resistance training programs lasting ≥8 weeks on strength, physical function, and body composition of adults ≥65 years old diagnosed with pre-sarcopenia, sarcopenia, pre-frailty, or frailty. A search from the earliest record up to and including December 2020 was carried out using the PubMed, Scopus, Web of Science, and Cochrane Library databases. A total of 25 studies (n = 2267 participants) were included. Meta-analysis showed significant changes in favour of resistance training for handgrip (ES = 0.51, p = 0.001) and lower-limb strength (ES = 0.93, p < 0.001), agility (ES = 0.78, p = 0.003), gait speed (ES = 0.75, p < 0.001), postural stability (ES = 0.68, p = 0.007), functional performance (ES = 0.76, p < 0.001), fat mass (ES = 0.41, p = 0.001), and muscle mass (ES = 0.29, p = 0.002). Resistance training during early stages had positive effects in all variables during early stages (ES > 0.12), being particularly effective in improving gait speed (ES = 0.63, p = 0.016) and functional strength (ES = 0.53, p = 0.011). Based on these results, resistance training should be considered as a highly effective preventive strategy to delay and attenuate the negative effects of sarcopenia and frailty in both early and late stages.
RESUMO
Drinking alkaline water after intense anaerobic exercise may enhance both cognitive and physical performance. This study aimed to investigate the effect of high mineral alkaline water consumed over three consecutive days on reaction time after anaerobic exercise in twelve healthy young males (aged 21.1 ± 1.3 years) with a valid sports medical examination. Participants were excluded when they took any medications or performance-enhancing supplements for the period of at least four weeks before the study commenced. Participants were randomly divided into two groups in this double-blind, placebo-controlled crossover pilot study. They ingested either alkaline water (AW) or regular table water ( RTW) for three consecutive days before anaerobic exercise. The anaerobic exercise consisted of two 2-min high-intensity step-tests with a passive rest interval of 3 minutes between the two bouts of exercise. Performance in the step-test (W), reaction time for visual and auditory signals, the rate of perceived exertion (RPE), urine specific gravity, and lactate concentration were analysed. No effect of AW was found on reaction time and the other variables except anaerobic performance. An-aerobic performance was significantly higher after ingestion of AW in both step-tests (p < 0.05). The ingestion of AW for three consecutive days before anaerobic exercise seems to positively affect anaerobic performance.