Movement competency and measures of isometric and dynamic strength and power in boys of different maturity status

An understanding of how movement competency, strength, and power interact with natural growth and maturation is required in order to determine meaningful changes with developing athletes. Isometric and dynamic testing in youth athletes provides insight into the natural development of the force-velocity (F-V) spectrum. Two-hundred and six young male athletes, aged 9-17 years of age, were grouped according to stage of maturation based on their maturity offset which was determined as number of years from peak height velocity (PHV). All participants performed the back-squat assessment (BSA), isometric mid-thigh pull (IMTP), countermovement jump (CMJ), and squat jump (SJ) tests. Absolute and scaled force-time variables were collected from the IMTP, CMJ, and SJ. No significant differences were observed between maturational groups for squat movement competency (P > .05). One-way ANOVA with Bonferroni post-hoc analysis revealed that increasing maturity led to significant, moderate to large increases in allometrically scaled peak force (PF_allo) for all tests (P < .05). Multiple stepwise linear regression models revealed IMTP PF_allo significantly predicted 34.8% and 41.3% of variance in SJ and CMJ jump height, respectively (P < .05). Natural growth and maturation induces positive adaptations to movement competency as well as isometric and dynamic strength and power. Trends from the IMTP, SJ, and CMJ tests indicate the largest differences in strength, and power may occur around the adolescent growth spurt despite the large variation in rates of change within the circa-PHV group.     

A common neural code for similar conscious experiences in different individuals

The interpretation of human consciousness from brain activity, without recourse to speech or action, is one of the most provoking and challenging frontiers of modern neuroscience. We asked whether there is a common neural code that underpins similar conscious experiences, which could be used to decode these experiences in the absence of behavior. To this end, we used richly evocative stimulation (an engaging movie) portraying real-world events to elicit a similar conscious experience in different people. Common neural correlates of conscious experience were quantified and related to measurable, quantitative and qualitative, executive components of the movie through two additional behavioral investigations. The movie’s executive demands drove synchronized brain activity across healthy participants’ frontal and parietal cortices in regions known to support executive function. Moreover, the timing of activity in these regions was predicted by participants’ highly similar qualitative experience of the movie’s moment-to-moment executive demands, suggesting that synchronization of activity across participants underpinned their similar experience. Thus we demonstrate, for the first time to our knowledge, that a neural index based on executive function reliably predicted every healthy individual’s similar conscious experience in response to real-world events unfolding over time. This approach provided strong evidence for the conscious experience of a brain-injured patient, who had remained entirely behaviorally nonresponsive for 16 y. The patient’s executive engagement and moment-to-moment perception of the movie content were highly similar to that of every healthy participant. These findings shed light on the common basis of human consciousness and enable the interpretation of conscious experience in the absence of behavior.Although consciousness is a part of all of our lives, we are not privy to the conscious experiences of others. Indeed, our ability to understand and appreciate their experiences depends largely on their self-report, or ability to describe those experiences (1). However, in recent years a population of patients has been identified who are demonstrably conscious, but entirely unable to speak or move willfully in any way, precluding any systematic investigation of their conscious experience of the world (2–8). It remains unknown whether there is a common neural code that can account for how different individuals might form similar conscious experiences and, if so, whether it could be used to interpret those experiences without recourse to self-report.The “executive” function of the brain refers to those processes that coordinate and schedule a host of other more basic cognitive operations, such as monitoring and analyzing information from the environment and integrating it with internally generated goals, as well as planning and adapting new behavioral schemas to take account of this information (9–11). As such, executive function is integral to our conscious experience of the world as prior knowledge is integrated into the current “state of play” to make predictions about likely future events. Accordingly, executive function may provide an empirical window by which the cognitive aspect of human conscious experience can be quantified. The behavioral and neuronal bases of executive function have been well studied in neuropsychological patients (12–14) and with functional neuroimaging (9, 12, 15–17), which confirm that executive function is supported by a network of brain regions, primarily involving the frontal lobes and the posterior parietal cortex (9, 12, 15–17). However, the open-ended nature of our conscious experiences combined with the narrowly defined scope of most tests of executive function, which rely on responses to specific parameters of a study task, make it challenging to relate executive function to consciousness in real-world situations.Movie viewing may provide a solution to this problem. By their very nature, engaging movies are designed to give viewers a shared conscious experience driven, in part, by the recruitment of similar executive processes, as each viewer continuously integrates their observations, analyses, and predictions, while filtering out any distractions, leading to an ongoing involvement in the movie’s plot. These cognitive, integrative processes are executive in the broad meaning of the word and go beyond processes directly related to planning and execution of motor behavior to encompass “second-order” or “meta” cognitive states that enable viewers to understand a movie. When different individuals watch the same movie, synchronized changes of brain activity across the individuals are observed (18–20). However, it is not known whether any of these synchronized activity fluctuations reflect similar executive function across different individuals in response to the evolving executive demands of the movie plot.We addressed this question in a series of studies by using a highly engaging short movie by Alfred Hitchcock, the so-called “master of suspense,” to drive the conscious experiences of three groups of healthy participants. Initially, the neural correlates of conscious experience common to different individuals were quantified using functional magnetic resonance imaging (fMRI). Subsequently, these correlates were related to measurable (quantitative and qualitative) executive components of the movie plot through two additional behavioral investigations in independent groups of healthy participants to determine the neural basis of executive processes common across individuals. We then applied the same approach in two behaviorally nonresponsive patients with unknown levels of consciousness to examine and quantify their experience of the world in the absence of self-report.     

Use of a Re-entry Device in Left Subclavian Occlusion: Case Series

CardioVascular and Interventional Radiology - To describe the use of a re-entry catheter in the endovascular treatment of left subclavian stenosis. We present three patients where initial attempts...     

Stimulus-specific suppression preserves information in auditory short-term memory

Philosophers and scientists have puzzled for millennia over how perceptual information is stored in short-term memory. Some have suggested that early sensory representations are involved, but their precise role has remained unclear. The current study asks whether auditory cortex shows sustained frequency-specific activation while sounds are maintained in short-term memory using high-resolution functional MRI (fMRI). Investigating short-term memory representations within regions of human auditory cortex with fMRI has been difficult because of their small size and high anatomical variability between subjects. However, we overcame these constraints by using multivoxel pattern analysis. It clearly revealed frequency-specific activity during the encoding phase of a change detection task, and the degree of this frequency-specific activation was positively related to performance in the task. Although the sounds had to be maintained in memory, activity in auditory cortex was significantly suppressed. Strikingly, patterns of activity in this maintenance period correlated negatively with the patterns evoked by the same frequencies during encoding. Furthermore, individuals who used a rehearsal strategy to remember the sounds showed reduced frequency-specific suppression during the maintenance period. Although negative activations are often disregarded in fMRI research, our findings imply that decreases in blood oxygenation level-dependent response carry important stimulus-specific information and can be related to cognitive processes. We hypothesize that, during auditory change detection, frequency-specific suppression protects short-term memory representations from being overwritten by inhibiting the encoding of interfering sounds.     

Survey of life support training in teachers and provision of automated external defibrillators in secondary schools in South Wales

BackgroundSudden cardiac death in young people accounts for about 45 deaths per year in Wales. Early intervention with defibrillation improves survival for cardiac arrest. A recent intervention providing an automated external defibrillator (AED) to every high school in New York state, USA, eliminated sudden cardiac death in young people under 19 years over a 2-year period. We conducted a postal survey to establish whether secondary schoolteachers in South Wales had life support training and access to an AED.MethodsAll physical education departments in South Wales secondary schools (n=158, identified from Welsh Audit Office data) were sent postal questionnaires in May, 2014. Teachers were asked to provide information including the level of life support training and access to an AED. Completed questionnaires returned within 14 days were included in the study.FindingsResponses were received from 35 schools (22%). Responses are representative of 2133 teachers who are responsible for 30 000 pupils aged 11–18 years. 200 teachers (9·6%) reported having in-date life support training and a further 21 (1·0%) had training that included use of an AED. Ten schools had an AED on site with a further two that had AEDs located at an adjacent leisure centre. Three of the schools with AEDs had no trained staff (odds ratio 1·04, 95% CI 0·58–1·90, p=0·89). 73% of the respondents (115/158) agreed that life support training should be a mandatory part of training.InterpretationThe results suggest that only a small number of teachers in South Wales have life support training and access to an AED, and yet most teachers questioned expressed a desire to be trained in life support and to have access to an AED. Limitations to this study include the low response rate, which could reflect an inherent bias in the methodology whereby only interested teachers or schools with AEDs on site replied to the survey. These initial findings warrant further investigation at a national level, which would include a feasibility study exploring the implementation of a nationwide AED provision and training programme in schools.FundingNone.     

Phenotypic analysis of mouse thymus development

In this review, we have presented some of our data on the developing mouse thymus studied using mAbs to cell surface determinants and FMF. In the past, numerous parameters have been used in an attempt to describe the differentiation of T cells in the thymus. These parameters have included relative cell size, anatomical location, enzyme activity (TdT), expression of surface molecules such as Thy-1, Lyt-1, H-2, PNA, T200, TL, and CD4/CD8, and the ability to express IL-2R [45, 46]. None of these parameters has been adequate to describe how the thymus generates functional ‘mature’ T cells, which now include CD4/CD8 single-positive and double-negative cells, from its small numbers of elusive precursors [17, 45, 47]. However, given the irrefutable evidence that the thymus does influence the repertoire of TcR expressed by cells generated therein [48], analysis of gene regulation and surface expression of TcR molecules by thymocytes is certainly the most promising approach for the elucidation of the mysterious nature of intrathymic T cell differentiation.