Study of the Mechanism of Perceived Rotational Acceleration of a Bionic Semicircular Canal on the Basis of the "Circular Geometry Hypothesis".

Academia often uses the "circular geometry hypothesis" to explain the sensing principle of the human semicircular canal (SCC) system for angular acceleration, which is widely accepted as an important angular acceleration sensor in the human balance system. On the basis of this hypothesis and the anatomical structure of human SCCs, a series of physical SCC models with different geometries at 4× magnification were prepared via three-dimensional printing and modification of hydrogels. Theoretical models of the SCC perception mechanism were established. Then, impulse angular acceleration, sinusoidal rotation, and sinusoidal linear stimulation were applied to the models, and their responses were visually observed and analyzed in detail. As a result, the circular SCC model had a larger system gain and a smaller phase difference for angular acceleration stimulation but a smaller system gain and a larger phase difference for linear acceleration stimulation. These results verified that the circular semicircular canal was more sensitive to angular acceleration. Our bionic model is hoped to be used for demonstrating the human SCC working process, facilitating researchers in better understanding of the working mechanism of the human SCC, or as a manual model for medical staff to simulate the diagnosis and treatment of human SCC.

EEG ß oscillations in aberrant data perception under cognitive load modulation.

Data-driven decision making (DDDM) is becoming an indispensable component of work across various fields, and the perception of aberrant data (PAD) has emerged as an essential skill. Nonetheless, the neural processing mechanisms underpinning PAD remain incompletely elucidated. Direct evidence linking neural oscillations to PAD is currently lacking, and the impact of cognitive load remains ambiguous. We address this issue using EEG time-frequency analysis. Data were collected from 21 healthy participants. The experiment employed a 2 (low vs. high cognitive load) × 2 [PAD+ (aberrant data accurately identified as aberrant) vs. PAD- (non-aberrant data correctly recognized as normal)] within-subject laboratory design. Results indicate that upper ß band oscillations (26-30 Hz) were significantly enhanced in the PAD + condition compared to PAD-, with consistent activity observed in the frontal (p < 0.001, [Formula: see text] = 0.41) and parietal lobes (p = 0.028, [Formula: see text] = 0.22) within the 300-350 ms time window. Additionally, as cognitive load increased, the time window of ß oscillations for distinguishing PAD+ from PAD- shifted earlier. This study enriches our understanding of the PAD neural basis by exploring the distribution of neural oscillation frequencies, decision-making neural circuits, and the windowing effect induced by cognitive load. These findings have significant implications for elucidating the pathological mechanisms of neurodegenerative disorders, as well as in the initial screening, intervention, and treatment of diseases.

A Spatio-Temporal Capsule Neural Network with Self-Correlation Routing for EEG Decoding of Semantic Concepts of Imagination and Perception Tasks.

Decoding semantic concepts for imagination and perception tasks (SCIP) is important for rehabilitation medicine as well as cognitive neuroscience. Electroencephalogram (EEG) is commonly used in the relevant fields, because it is a low-cost noninvasive technique with high temporal resolution. However, as EEG signals contain a high noise level resulting in a low signal-to-noise ratio, it makes decoding EEG-based semantic concepts for imagination and perception tasks (SCIP-EEG) challenging. Currently, neural network algorithms such as CNN, RNN, and LSTM have almost reached their limits in EEG signal decoding due to their own short-comings. The emergence of transformer methods has improved the classification performance of neural networks for EEG signals. However, the transformer model has a large parameter set and high complexity, which is not conducive to the application of BCI. EEG signals have high spatial correlation. The relationship between signals from different electrodes is more complex. Capsule neural networks can effectively model the spatial relationship between electrodes through vector representation and a dynamic routing mechanism. Therefore, it achieves more accurate feature extraction and classification. This paper proposes a spatio-temporal capsule network with a self-correlation routing mechaninsm for the classification of semantic conceptual EEG signals. By improving the feature extraction and routing mechanism, the model is able to more effectively capture the highly variable spatio-temporal features from EEG signals and establish connections between capsules, thereby enhancing classification accuracy and model efficiency. The performance of the proposed model was validated using the publicly accessible semantic concept dataset for imagined and perceived tasks from Bath University. Our model achieved average accuracies of 94.9%, 93.3%, and 78.4% in the three sensory modalities (pictorial, orthographic, and audio), respectively. The overall average accuracy across the three sensory modalities is 88.9%. Compared to existing advanced algorithms, the proposed model achieved state-of-the-art performance, significantly improving classification accuracy. Additionally, the proposed model is more stable and efficient, making it a better decoding solution for SCIP-EEG decoding.

Selective consistency of recurrent neural networks induced by plasticity as a mechanism of unsupervised perceptual learning.

Understanding the mechanism by which the brain achieves relatively consistent information processing contrary to its inherent inconsistency in activity is one of the major challenges in neuroscience. Recently, it has been reported that the consistency of neural responses to stimuli that are presented repeatedly is enhanced implicitly in an unsupervised way, and results in improved perceptual consistency. Here, we propose the term "selective consistency" to describe this input-dependent consistency and hypothesize that it will be acquired in a self-organizing manner by plasticity within the neural system. To test this, we investigated whether a reservoir-based plastic model could acquire selective consistency to repeated stimuli. We used white noise sequences randomly generated in each trial and referenced white noise sequences presented multiple times. The results showed that the plastic network was capable of acquiring selective consistency rapidly, with as little as five exposures to stimuli, even for white noise. The acquisition of selective consistency could occur independently of performance optimization, as the network's time-series prediction accuracy for referenced stimuli did not improve with repeated exposure and optimization. Furthermore, the network could only achieve selective consistency when in the region between order and chaos. These findings suggest that the neural system can acquire selective consistency in a self-organizing manner and that this may serve as a mechanism for certain types of learning.

Do Different Playing Formats and Aerobic Capacity Influence Variances in Psychophysiological Demands and Technical Performance in Small-Sided Games? A Study among Under-17 Male Soccer Players.

This study aimed to: (i) analyze the variations in psychophysiological demands (mean heart rate, meanHR; rate of perceived exertion, RPE) and technical performance (umber of successful and unsuccessful passes, and occurrences of ball loss) between 2v2 and 4v4 small-sided games (SSGs) formats, and (ii) examine the relationships of aerobic capacity measured in Yo-Yo Intermittent Recovery Test (YYIRT) on psychophysiological and technical performance during SSGs. This study used a cross-sectional design with repeated measures, where the same players participated in both 2v2 and 4v4 formats across two training sessions per format. Twenty-four talent/developmental male youth soccer players, aged 16.6 ± 0.5 years. The meanHR, measured through heart rate sensors, the RPE, assessed using the CR6-20 scale, and the number of successful and unsuccessful passes, along with occurrences of ball loss, recorded using an ad hoc observational tool, were evaluated in each repetition. Players during the 2v2 format had significantly greater mean HR (+4.1%; p < 0.001; d = 2.258), RPE (+12.2%; p < 0.001; d = 2.258), successful passes (+22.2%; p = 0.006; d = 0.884), unsuccessful passes (+62.5%; p < 0.001; d = 1.197) and lost balls (+111.1%; p < 0.001; d = 2.085) than 4v4 format. The YYIRT was significantly and largely correlated with unsuccessful passes (r = 0.502; p = 0.012) and lost balls (r = 0.421; p = 0.041) in 2v2 format. In conclusion, this study suggests that engaging in 2v2 activities constitutes a more intense form of practice, significantly enhancing individual participation in technical aspects. Moreover, aerobic capacity may influence the smaller formats of play and how players perform key technical actions. Therefore, coaches must consider this to ensure the necessary performance in such games.

When sensory input meets spontaneous brain activity.

A recent study by Wu, Podvalny, and colleagues investigated how ongoing spontaneous brain activity interacts with sensory input and shapes conscious perception. It reports diverse effects of prestimulus activity in several key networks, revealing new roles of the prefrontal cortex and the default mode network in perception and consciousness.

The Effect of a Synthetic-Grass Sport Surface on Physiology and Perception During Intermittent Exercise in Hot Conditions.

PURPOSE: The current study aimed to determine the effect of a synthetic-grass sport surface on core body temperature, skin temperature, heart rate, thermal sensation, thermal comfort, and rating of perceived exertion (RPE) during intermittent exercise in hot conditions. METHODS: Using a randomized crossover design, 13 trained/developmental team-sport athletes completed two 50-minute standardized intermittent running protocols on a synthetic and a natural-grass surface, on separate days (control-condition air temperature 32.6 °C [1.3 °C], relative humidity 43.2% [5.3%]). RESULTS: Final skin temperature was significantly higher on synthetic compared with natural grass at the calf (40.1 °C [2.5 °C] vs 33.4 °C [0.6 °C]; P < .001), shoulder (36.6 °C [1.7 °C] vs 33.7 °C [0.7 °C]; P < .001), and chest (33.2 °C [1.1 °C] vs 31.8 °C [1.2 °C]; P = .02). Thermal sensation (median: 2.3; interquartile range [0.5] vs 2.2 [0.5], P = .03) and sweat rate (1.5 [0.4] L·h-1 vs 1.2 [0.3] L·h-1; P = .02) were also significantly higher on synthetic grass. While final core body temperature was significantly higher on the natural than synthetic grass (38.4 °C [0.3 °C] vs 38.2 °C [0.4 °C]), there were no significant differences in delta core temperature, as well as heart rate, thermal comfort, or RPE. CONCLUSIONS: Higher skin temperatures, thermal sensation, and sweat rates suggest that exercising on synthetic grass in hot conditions may increase some markers of heat strain during exercise. However, delta core body temperature, heart rate, thermal comfort, and RPE remained unaffected.

Perceptions of menstrual cycle tracking among elite rugby players.

The purpose of the current study was to understand female rugby players' perceptions of menstrual cycle (MC) tracking and identify the impact of MC tracking for the players. Interpretive descriptive methodology was adopted. Interviews were conducted with 12 elite female rugby players (age 25.2 ± 4.3 years), who were all naturally menstruating. Data were analysed following the four stages recommended within Interpretive Description. Results identified that athletes obtain personal benefits from MC tracking by; enhancing understanding of their MC and symptoms, and responding to their MC and symptoms. Athletes also reported that the process of tracking their MC enhanced relationships by; improving communication and interactions with coaches and support staff, and by facilitating team support. Specifically, using tracking increased the opportunities for open conversations with coaches, support staff and teammates regarding their MC. Overall, the findings highlight benefits of menstrual cycle tracking within this group of naturally menstruating rugby players, particularly in helping players and coaches understand the individual nature of the MC, engage in conversations, and establish support from teammates.

Evolution, perception, and the mind.

The classical mind-body problem persists as one of the deepest scientific mysteries. Despite the grand claims of the new AI, some of the most basic facts of human vision cannot be explained by current or proposed theories of brain structure and function. This paper reviews some well-known mysteries including the neural binding problem, blind sight, subjective experience and prosthetics. There is continuing progress, but the core mysteries of the mind seem to require fundamental advances for any reductionist resolution.

Gaelic Games Players' and Practitioners' Perceptions of Recovery Strategies.

PURPOSE: This study both investigated and compared Gaelic games players' and practitioners' perceptions of the importance of postexercise recovery strategies. METHODS: Gaelic players (n = 1178 [n = 574 female], age 24.6 [6.6] y) and practitioners (n = 148 [n = 29 female], age 35.9 [8.7] y) completed a questionnaire assessing their perceptions of various postexercise recovery strategies (importance ranked out of 5 [1 "not important at all" to 5 "extremely important"]). Players were further categorized by playing standard into developmental (club/collegiate; n = 869) and national (intercounty; n = 309) levels and by sport: Gaelic football (n = 813), camogie/hurling (n = 342), and Gaelic handball (n = 23). Practitioners were categorized as sport coaches (n = 67), strength and conditioning staff (n = 34), nutrition staff (n = 15), and athletic rehabilitation staff (n = 32). RESULTS: Gaelic players prevalently perceived sleep (76.4%), rehydration (72.5%), postexercise meal (48.4%), stretching (47.6%), active cool-down (25.1%), foam rolling (23.1%), and massage by therapist (22.6%) as "extremely important." Practitioners prevalently perceived sleep (90.1%), rehydration (83.6%), postexercise meal (76.6%), daytime naps (36.2%), stretching (25.4%), discussion with teammates (24.6%), and getting into nature (19.4%) as "extremely important." CONCLUSIONS: While strategies with well-documented efficacy such as sleep, nutrition, and rehydration were rated as most important, a distinct and possibly problematic disconnect exists between the perceived importance of many strategies and their empirically demonstrated effectiveness. For instance, active cool-downs and stretching were perceived as highly important despite prevailing evidence suggesting that their effects are often small in magnitude. Collectively, work promoting optimal recovery practices and aligning player-practitioner perspectives would be beneficial to maximize time and resource allocation and enhance player buy-in.

Between fear of death and just a warning sign: Seizure severity scales neglect the subjective quality of periictal perceptions.

The burden of epilepsy is not only related to seizure frequency; the severity of epileptic seizures considerably affects patient's lives. A number of seizure severity scales have thus been developed for a systematic assessment. Items considered relevant in these scales mainly pertain to objective features, such as seizure duration, loss of consciousness, and seizure-related injuries. In contrast, subjective experiences of seizures are considered only in their functionality as "warnings", whereas the quality of subjective perceptions and feelings are disregarded phenomena. This leads to a gap between the often-distressing subjective experiences which people with epilepsy remember from their seizures and the perception of physicians which may negatively impact physician-patient communication and interaction and question their valid use as treatment outcomes. We advocate here to develop new seizure severity assessments in collaboration with patient organizations which integrate also the subjective quality of seizures.

Self-Reported Menstrual Health, Symptomatology, and Perceived Effects of the Menstrual Cycle for Elite Junior and Senior Football Players.

PURPOSE: To describe the self-reported menstrual health, symptomatology, and perceived effects of the menstrual cycle on athletic performance for national and international Australian football (soccer) players. METHODS: Players from national and domestic teams were invited to complete an online questionnaire regarding menstrual health, use of hormonal contraceptives (HCs), negative symptomatology, and perceived disruption of the menstrual cycle to performance. Descriptive statistics and binomial regressions with odds ratios (OR) were used to report the relationship of menstrual-related variables with perceived performance disruption. RESULTS: A total of 199 players (20.9 [5.1] y) completed the questionnaire, with 18% of players reporting using HCs. One primary amenorrhea case was detected, and 26% of players reported menarche at age ≥15 years. For non-HC users, the prevalence of secondary amenorrhea was 2%, oligomenorrhea was 19%, and heavy menstrual bleeding was 11%. Ninety-seven percent of players reported experiencing physical or affective menstrual symptoms (5 [1.3] per player), and 40% of all players reported that menstrual symptoms impacted their ability to work, study, train, or compete. Furthermore, 40% of players perceived their training or performance to be disrupted by the menstrual cycle. Increasing number of menstrual symptoms (OR = 1.43; 95% CI, 1.28-1.62; P < .001), heavy menstrual bleeding (OR = 12.73; 95% CI, 3.4-82.8; P < .001), and pelvic pain (OR = 3.40; 95% CI, 1.7-7.2; P < .001) increased the likelihood of perceiving the menstrual cycle to disrupt performance. CONCLUSION: Heavy menstrual bleeding and HC use were low among this cohort of national and international footballers, whereas amenorrhea and oligomenorrhoea were comparable with other football populations. Nearly all players reported menstrual symptoms, and increased symptomatology was associated with greater perceived effects on performance.

Identifying profiles of actual and perceived motor competence measured with aligned instruments: Differences in (enjoyment of) physical fitness.

A person-centred approach was used to examine whether children with various actual and perceived motor competence (AMC and PMC) profiles differ in (enjoyment of) physical fitness (PF). The strength of the relationship between AMC and PMC was also assessed through aligned assessment tools. A sample of 287 7-11-year-old children (47.40% boys, Mage = 8.92 ± .78 years) was assessed on AMC with the KörperkoordinationsTest für Kinder (KTK3), and on PF with six validated fitness tests. Animated videos fully aligned with the AMC- and PF-tests were used to assess children's PMC and enjoyment of PF, respectively. Cluster analyses identified one convergent (i.e. high AMC-high PMC) and three partially convergent AMC-PMC profiles (i.e. low AMC-high PMC). Furthermore, children with relatively high AMC (i.e. high-average profile) reported higher PF (F = 30.99, p < .001), while children with relatively high PMC (i.e. average-high profile) reported higher enjoyment of PF (F = 9.02, p < .001). The correlation between AMC and PMC was significant but weak (r = .16). Overall, it seems important to invest in both children's AMC and PMC as they may support a higher (enjoyment of) PF, potentially leading to higher PA-levels.

When it comes to physical fitness, actual motor competence rather than perceived motor competence seemed to play the biggest role. As extra high perceived motor competence did not add additional benefits in terms of physical fitness, there might have been a ceiling effect of perceived motor competence.When looking at enjoyment of physical fitness, perceived motor competence seemed to be a more important factor than actual motor competence. However, profile analyses revealed that a relatively high perceived motor competence score may not fully compensate the loss of enjoyment in physical fitness when children's actual motor competence is relatively low.

Examining the alignment between subjective effort and objective force production.

Ratings of Perceived Exertion (RPE) are frequently used to prescribe exercise intensity. A central assumption of using RPE scales is that the subjective perception of effort maps onto objective performance in a consistent way. However, the degree and shape of how RPE aligns with objective performance is not fully understood. Here, we investigate the degree and shape of alignment, as well as how time (i.e., how frequently an effort needs to be performed) and mental effort (i.e., if one has to invest mental effort and physical effort) correspond with the alignment. In a randomized within-subjects experiment, we used a grip-to-scale method that asked participants (N = 43) to repeatedly squeeze a handgrip dynamometer with four to-be-produced RPE target levels relative to their subjective maximum strength (representing 20%, 40%, 60%, or 80%). We found that the RPE-force alignment was not the same across RPE-levels: Whereas subjective differences from 20-40% and 40-60% were met by comparable differences in produced force, a substantially larger difference was observed for the 60-80% interval. Interestingly, exploratory post-hoc analyses revealed that this was mirrored by an increase in variance at the higher effort levels. In addition, at constant RPE-levels, participants produced less force over time, and this effect was more pronounced at lower RPE target levels. Lastly, anticipating mental effort after the physical effort slightly altered the alignment as a function of the to-be-produced RPE-level and experimental duration. Taken together, our results indicate that the mapping of perceived effort on objective performance is intricate, and several factors affect the degree and shape of how RPE and performance align. Understanding the dynamic adjustment of RPE-performance alignment across different RPE levels is particularly relevant for contexts that use RPE as a tool for training load prescription.

Estimating Muscle Fiber-Type Composition in Elite Athletes: A Survey on Current Practices and Perceived Merit.

PURPOSE: To gather information on practices and perceptions of high-performance experts regarding their athletes' muscle fiber-type composition (MFTC) and its estimation. METHODS: A questionnaire on the noninvasive versus invasive estimation of MFTC was completed by 446 experts including coaches and sport-science/sports-medicine staff. Moreover, the perceived importance of MFTC for training and performance optimization was assessed. Differences between sport types (individual and team sports) were analyzed using chi-square tests. RESULTS: Forty percent of the experts implemented MFTC assessment in pursuit of performance optimization, while 50% did not know their athletes' MFTC but expressed a desire to implement it if they would be able to assess MFTC. Ten percent did not perceive value in MFTC assessment. Only 18% of experts believed that their athletes would undergo a muscle biopsy, leading to the adoption of alternative noninvasive techniques. Experts primarily relied on their experience to estimate MFTC (65%), with experts working in individual sports using their experience more frequently than those working in team sports (68% vs 51%; P = .009). Jump tests emerged as the second-most commonly employed method for estimating MFTC (56%). When only considering experts who are currently using MFTC, 87% use MFTC to individualize training volume and 84% to individualize training intensity. CONCLUSIONS: Experts value MFTC assessment primarily to individualize training but mainly rely on noninvasive methods to estimate MFTC. Some of these methods lack scientific validity, suggesting a continuing need for education and further research in this area.

Training loads and microcycle periodisation in Italian Serie A youth soccer players.

Microcycles are fundamental structures for training prescription and load management, helping to optimise training effects and performance. This study quantified external and internal loads of Italian Serie A youth soccer players across competitive weeks and their periodisation within microcycles. Data were collected from 90 players belonging to four age groups (under-19, -17, -16, -15) across a season. Methods of monitoring external [duration and global navigation satellite systems (GNSS)] and internal load [heart rate (HR) and rating of perceived exertion (RPE)] were employed. Linear mixed models determined differences in training loads across age groups, training days and player positions. Under-19 and under-17 players trained five times per week, while younger players trained four times. Late-stage academy players (under-19 and -17) demonstrated higher weekly accumulated external and sRPE training load compared to their younger counterparts (p < 0.05 between groups). Weekly accumulated HR internal loads were higher in under-15 players (p < 0.05 between groups). Marked fluctuations of daily load were observed across microcycles in under-19 and under-17 groups (p < 0.05 between days). These findings highlight progressive increases in training load throughout the development pathway, with late-stage academy players training with higher frequency, volume and marked periodisation compared to younger players.

Post-exercise hot or cold water immersion does not alter perception of effort or neuroendocrine responses during subsequent moderate-intensity exercise.

Post-exercise hot (HWI) and cold (CWI) water immersion are popular strategies used by athletes in a range of sporting contexts, such as enhancing recovery or adaptation. However, prolonged heating bouts increase neuroendocrine responses that are associated with perceptions of fatigue. Fourteen endurance-trained runners performed three trials consisting of two 45-min runs at 95% lactate threshold on a treadmill separated by 6 h of recovery. Following the first run, participants completed one of HWI (30 min, 40°C), CWI (15 min, 14°C) or control (CON, 30 min rest in ambient conditions) in a randomised order. Perceived effort and recovery were measured using ratings of perceived exertion (RPE) and the Acute Recovery and Stress Scale (ARSS), whilst physiological responses including venous concentrations of a range of neuroendocrine markers, superficial femoral blood flow, heart rate and rectal temperature were measured. Exercise increased neuroendocrine responses of interleukin-6, adrenaline and noradrenaline (all P < 0.001). Additionally, perceptions of overall recovery (P < 0.001), mental performance capacity (P = 0.02), physical performance capability (P = 0.01) and emotional balance (P = 0.03) were reduced prior to the second run. However, there was no effect of condition on these variables (P > 0.05), nor RPE (P = 0.68), despite differences in rectal temperature, superficial femoral blood flow following the first run, and participants' expected recovery prior to the intervention (all P < 0.001). Therefore, athletes may engage in post-exercise hot or cold-water immersion without negatively impacting moderate-intensity training sessions performed later the same day.

Sensing and feeling: an overview.

Emotional experiences are driven, in part, by the way we process and integrate information from different sensory modalities. Understanding how perceptual and emotional systems interact to give rise to subjective feelings is an important, complex and challenging issue, requiring new approaches and integrative thinking that fuses the fundamentals of low-level sensory perception with higher-level cognitive and affective processes. The Theme Issue 'Sensing and feeling: an integrative approach to sensory processing and emotional experience' showcases fifteen theoretical, empirical, and review articles from experts working at the intersection of perception and emotion, encompassing multiple sensory systems (visual, auditory, tactile and interoceptive), clinical and non-clinical perspectives (e.g. affective disorders and hearing loss), contextual and social perspectives, and complex emotional experiences in special populations. Articles in Part 1 emphasize recent advances across fields in sensory and emotion science and give insights into future directions. Each article in Part 2 provides more detailed and specific methodological approaches or theoretical models, and focuses on basic mechanisms linking sensation to emotional experience. This article is part of the theme issue 'Sensing and feeling: an integrative approach to sensory processing and emotional experience'.