Passive Conditions Research Articles

Place conditioning as evaluation of affective valence in piglets

The emotional valence of animals is challenging to assess, despite being a key component of welfare. In this study, we attempted to assess emotional valence through memory in 1- and 3-week-old piglets. It was hypothesized that piglets would spend less time in a pen where they experienced a negative event (castration) and more time in a pen where they experienced a positive event (enrichment). A testing apparatus was designed with three equally sized pens: two outer sections serving as treatment pens containing unique visual and tactile cues and a center section remaining neutral. Piglets received either negative or positive condition in one outer treatment pen and a sham treatment in the opposite. Various methods were tested (age of piglets, number and length of conditioning sessions, passive vs. active conditioning). Contrary to expectations, piglets did not decrease their time in the pen associated with the negative condition or increase their time in the pen associated with the positive condition. However, when exposed to the positive condition, results indicate older piglets developed an aversion towards the sham treatment. This study provides methodological groundwork for the application of place conditioning in piglets and highlights the nuances important for the use of cognitive tests to assess animal welfare.

Assessing consciousness in acute coma using name-evoked responses

Detecting consciousness in clinically unresponsive patients remains a significant challenge. Existing studies demonstrate that electroencephalography (EEG) can detect brain responses in behaviorally unresponsive patients, indicating potential for consciousness detection. However, most of this evidence is based on chronic patients, and there is a lack of studies focusing on acute coma cases. This study aims to detect signs of residual consciousness in patients with acute coma by using bedside EEG and electromyography (EMG) during an auditory oddball paradigm. We recruited patients with acute brain injury (either traumatic brain injury or cardiac arrest) who were admitted to the intensive care unit within two weeks after injury, with a Glasgow Coma Scale (GCS) score of 8 or below. Auditory stimuli included the patients' own names and other common names (referred to as standard names), spoken by the patients’ relatives, delivered under two conditions: passive listening (where patients were instructed that sounds would be played) and active listening (where patients were asked to move hands when heard their own names). Brain and muscle activity were recorded using EEG and EMG during the auditory paradigm. Event-related potentials (ERP) and EMG spectra were analyzed and compared between responses to the subject’s own name and other standard names in both passive and active listening conditions. A total of 22 patients were included in the final analysis. Subjects exhibited enhanced ERP responses when exposed to their own names, particularly during the active listening task. Compared to standard names or passive listening, distinct differences in brain network connectivity and increased EMG responses were detected during active listening to their own names. These findings suggest the presence of residual consciousness, offering the potential for assessing consciousness in behaviorally unresponsive patients.

Ascending Vagal Sensory and Central Noradrenergic Pathways Modulate Retrieval of Passive Avoidance Memory in Male Rats.

Visceral feedback from the body is often subconscious, but plays an important role in guiding motivated behaviors. Vagal sensory neurons relay "gut feelings" to noradrenergic (NA) neurons in the caudal nucleus of the solitary tract (cNTS), which in turn project to the anterior ventrolateral bed nucleus of the stria terminalis (vlBNST) and other hypothalamic-limbic forebrain regions. Prior work supports a role for these circuits in modulating memory consolidation and extinction, but a potential role in retrieval of conditioned avoidance remains untested. To examine this, adult male rats underwent passive avoidance conditioning. We then lesioned gut-sensing vagal afferents by injecting cholecystokinin-conjugated saporin toxin (CSAP) into the vagal nodose ganglia (Experiment 1), or lesioned NA inputs to the vlBNST by injecting saporin toxin conjugated to an antibody against dopamine-beta hydroxylase (DSAP) into the vlBNST (Experiment 2). When avoidance behavior was later assessed, rats with vagal CSAP lesions or NA DSAP lesions displayed significantly increased conditioned passive avoidance. These new findings support the view that gut vagal afferents and the cNTSNA-to-vlBNST circuit play a role in modulating the expression/retrieval of learned passive avoidance. Overall, our data suggest a dynamic modulatory role of vagal sensory feedback to the limbic forebrain in integrating interoceptive signals with contextual cues that elicit conditioned avoidance behavior.

Systemic neurophysiological entrainment to behaviorally relevant rhythmic stimuli.

Physiological oscillations, such as those involved in brain activity, heartbeat, and respiration, display inherent rhythmicity across various timescales. However, adaptive behavior arises from the interaction between these intrinsic rhythms and external environmental cues. In this study, we used multimodal neurophysiological recordings, simultaneously capturing signals from the central and autonomic nervous systems (CNS and ANS), to explore the dynamics of brain and body rhythms in response to rhythmic auditory stimulation across three conditions: baseline (no auditory stimulation), passive auditory processing, and active auditory processing (discrimination task). Our findings demonstrate that active engagement with auditory stimulation synchronizes both CNS and ANS rhythms with the external rhythm, unlike passive and baseline conditions, as evidenced by power spectral density (PSD) and coherence analyses. Importantly, phase angle analysis revealed a consistent alignment across participants between their physiological oscillatory phases at stimulus or response onsets. This alignment was associated with reaction times, suggesting that certain phases of physiological oscillations are spontaneously prioritized across individuals due to their adaptive role in sensorimotor behavior. These results highlight the intricate interplay between CNS and ANS rhythms in optimizing sensorimotor responses to environmental demands, suggesting a potential mechanism of embodied predictive processing.

Maintained volitional activation of the muscle alters the cortical processing of proprioceptive afference from the ankle joint

Cortical proprioceptive processing of intermittent, passive movements can be assessed by extracting evoked and induced electroencephalographic (EEG) responses to somatosensory stimuli. Although the existent prior research on somatosensory stimulations, it remains unknown to what extent ongoing volitional muscle activation modulates the proprioceptive cortical processing of passive ankle-joint rotations.Twenty-five healthy volunteers (28.8 ± 7 yr, 14 males) underwent a total of 100 right ankle-joint passive rotations (4° dorsiflexions, 4 ± 0.25 s inter-stimulus interval, 30°/s peak angular velocity) evoked by a movement actuator during passive condition with relaxed ankle and active condition with a constant plantarflexion torque of 5 ± 2.5 Nm. Simultaneously, EEG, electromyographic (EMG) and kinematic signals were collected. Spatiotemporal features of evoked and induced EEG responses to the stimuli were extracted to estimate the modulation of the cortical proprioceptive processing between the active and passive conditions.Proprioceptive stimuli during the active condition elicited robustly ∼26 % larger evoked response and ∼38 % larger beta suppression amplitudes, but ∼42 % weaker beta rebound amplitude over the primary sensorimotor cortex than the passive condition, with no differences in terms of response latencies.These findings indicate that the active volitional motor task during naturalistic proprioceptive stimulation of the ankle joint enhances related cortical activation and reduces related cortical inhibition with respect to the passive condition. Possible factors explaining these results include mechanisms occurring at several levels of the proprioceptive processing from the peripheral muscle (i.e. mechanical, muscle spindle status, etc.) to the different central (i.e. spinal, sub-cortical and cortical) levels.

A Dual Role for the Dorsolateral Prefrontal Cortex (DLPFC) in Auditory Deviance Detection.

In the oddball paradigm, the dorsolateral prefrontal cortex (DLPFC) is often associated with active cognitive responses, such as maintaining information in working memory or adapting response strategies. While some evidence points to the DLPFC's role in passive auditory deviance perception, a detailed understanding of the spatiotemporal neurodynamics involved remains unclear. In this study, event-related optical signals (EROS) and event-related potentials (ERPs) were simultaneously recorded for the first time over the prefrontal cortex using a 64-channel electroencephalography (EEG) system, during passive auditory deviance perception in 12 right-handed young adults (7 women and 5 men). In this oddball paradigm, deviant stimuli (a 1500 Hz pure tone) elicited a negative shift in the N1 ERP component, related to mismatch negativity (MMN), and a significant positive deflection associated with the P300, compared to standard stimuli (a 1000 Hz tone). We hypothesize that the DLPFC not only participates in active tasks but also plays a critical role in processing deviant stimuli in passive conditions, shifting from pre-attentive to attentive processing. We detected enhanced neural activity in the left middle frontal gyrus (MFG), at the same timing of the MMN component, followed by later activation at the timing of the P3a ERP component in the right MFG. Understanding these dynamics will provide deeper insights into the DLPFC's role in evaluating the novelty or unexpectedness of the deviant stimulus, updating its cognitive value, and adjusting future predictions accordingly. However, the small number of subjects could limit the generalizability of the observations, in particular with respect to the effect of handedness, and additional studies with larger and more diverse samples are necessary to validate our conclusions.

The effect of surgical procedure in the nasal cavity in rats on the passive avoidance conditioning and the level of monoamines in the hypothalamus

In a biological model of septoplasty in rats, the effect of the operation on the passive avoidance conditioning (PAC) was studied. It has been shown that septoplasty increases anxiety and reduces exploratory activity in rodents under PAC. Neurochemical analysis of the hypothalamus carried out immediately after the end of the experiment revealed an increase in norepinephrine metabolism in rats after septoplasty, which may be associated with activation of the hypothalamic-pituitary-adrenal axis.

Passive earth pressure on vertical rigid walls with negative wall friction coupling statically admissible stress field and soft computing

It is well known that the roughness of a wall plays a crucial role in determining the passive earth pressure that is exerted on a rigid wall. While the effects of positive wall roughness have been extensively studied in the past few decades, the study of passive earth pressure with negative wall friction is rarely found in the literature. This study aims to provide a precise solution for negative friction walls under passive wall conditions. The research is initiated by adopting a radial stress field for the cohesionless backfill and employs the concept of stress self-similarity. The problem is then formulated in a way that a statically admissible stress field be developed throughout an analyzed domain using a two-step numerical framework. The framework involves the successful execution of numerical integration, which leads to the exploration of the statically admissible stress field in cohesionless backfills under negative wall friction. This, in turn, helps to shed light on the mechanism of load transfer in such situations so that reliable design charts and tables be provided for practical uses. The study continues with a soft computing model that leads to more robust and effective designs for earth-retaining structures under various negative wall frictions and sloping backfills.

Performance evaluation of a novel semi-active absorption and isolation co-control strategy with magnetorheological seat suspension for commercial vehicle

Abstract Vibration isolation performance of seat suspension plays a critical role in protection of drive’s physical health as the last barrier. In this paper, the integrated magnetorheological (MR) dynamic tuned mass damper (TMD) is firstly designed and utilized into seat suspension. A semi-active co-control algorithm with MR damper and MR TMD is designed, analyzed and validated by comparative experiments. The dynamic models of two MR devices have been tested and fitted. Comparing with simulation and experimental results under various excitations and control conditions, this co-control algorithm with MR TMD is validated to be highly effective. The transmissibility at resonance frequency reaches to 0.81 which is less than 1. This phenomenon has hardly been investigated in seat suspension. It illustrates that resonance has been suppressed and improved significantly. The peak acceleration decreases to 1.19 m s−2 with a reduction of 57.2%, in contrast to passive condition with MR damper. The comfort index is increased by 45.6% under random excitation than passive condition. According to these comparisons, the vibration isolation property and comfort of seat suspension can be further improved by the proposed co-control algorithm with two MR devices.

Latent profile analysis of mental health in postgraduates: The impact of mentally-passive or active screen time and sedentary behaviors

Background and aimsThe mental health and lifestyle of students in higher education are recognized as critical areas for enhancing the quality of higher education. However, current research primarily focused on undergraduates, with a scarcity of studies examining the lifestyle and mental health of postgraduates. This study aimed to investigate the relationship between sedentary behaviors, screen time, and mental health among postgraduates, with a particular emphasis on comparing the effects of mental-active versus passive conditions. MethodsA survey of 633 postgraduates from Beijing Sport University measured indicators of mental health, screen time (ST), and sedentary behaviors (SB). Data were analyzed using SPSS for multiple linear regression and multiple logistic regression, and Mplus for latent profile analysis (LPA) to identify mental health profiles. ResultsFour profiles emerged: moderate (5.39%), flourishing (46.38%), languishing (41.19%), struggling (7.05%). At group level, the findings revealed that both mentally-passive ST and SB are significantly and positively associated with anxiety and video addiction. The results also indicated that, at individual level, mentally-passive ST had a greater impact on “flourishing” individuals, particularly when it ranged from 120 to 240 min per day. Conversely, mentally-active ST had a more significant influence on “moderate” individuals, especially when it occurred for 120–240 min per day. ConclusionThis study revealed the complexity of mental health among postgraduates and the patterns of association between mentally-passive or active ST and SB with different mental health subtypes, providing empirical evidence for interventions addressing mental health issues among postgraduate students.

Antibodies to Glutamate Reduce the IL-6 Content in Cerebral Structures in Mice with Age-Related Memory Impairment.

Intranasal administration of antibodies to glutamate for 14 days improved passive avoidance conditioning and reduces the content of IL-6 within 7 days after their withdrawal in the prefrontal cortex and hippocampus of aging C57BL/6 mice.

Assessment of a beeswax-packed domestic solar dryer for sustainable bitter gourd drying: An experimental study

Solar dryers present a clean and affordable solution to food wastage which is one of the biggest concerns of the world. The highest contribution of domestic sector to the global food waste and lack of researches on small-scale solar dryers have created a need to develop sustainable and low cost domestic solar dryers. The present research aims to develop and analyse the output behaviour of a beeswax-packed domestic solar dryer (BDSD) for intermittent bitter gourd drying. The drying kinetics of bitter gourd slices and thermal, economic, environmental and exergetic performances of the BDSD have been evaluated with varying sample masses for passive and active drying conditions. The average final moisture content of the bitter gourd slices for passive and active conditions were found to be 3.26 and 3.93 % (wb), respectively. Midilli-Kucuk model exhibited the strongest fit to the bitter gourd drying behaviour under both the drying conditions. The total moisture evaporation, heat transfer coefficients, thermal efficiency, specific moisture extraction rate, savings for dried bitter gourd slices drying, CO2 mitigation, carbon credit earned and exergy efficiency were found to increase while the drying rate, effective moisture diffusivity, specific energy consumption, costs for bitter gourd slices drying, payback period and energy payback time decreased as the sample mass increased under both drying conditions. The performance of the BDSD was found to be a linear function of sample mass under both drying conditions.

Single neuron responses to perceptual difficulty in the mouse auditory cortex.

Perceptual learning leads to improvement in behavioral performance, yet how the brain supports challenging perceptual demands is unknown. We used two photon imaging in the mouse primary auditory cortex during behavior in a Go-NoGo task designed to test perceptual difficulty. Using general linear model analysis, we found a subset of neurons that increased their responses during high perceptual demands. Single neurons increased their responses to both Go and NoGo sounds when mice were engaged in the more difficult perceptual discrimination. This increased responsiveness contributes to enhanced cortical network discriminability for the learned sounds. Under passive listening conditions, the same neurons responded weaker to the more similar sound pairs of the difficult task, and the training protocol by itself induced specific suppression to the learned sounds. Our findings identify how neuronal activity in auditory cortex is modulated during high perceptual demands, which is a fundamental feature associated with perceptual improvement.

How to activate threat perceptions in behavior research: A simple technique for inducing health and resource scarcity threats.

Understanding our cognitive and behavioral reactions to large-scale collective problems involving health and resource scarcity threats, such as the COVID-19 pandemic, helps usbe better prepared for future collective threats. However, existing studies on these threats tend to be restricted to correlational data, partly due to a lack of reliable experimental techniques for manipulating threat perceptions. In four preregistered experiments (N = 5152), we developed and validated an experimental technique that can separately activate perceptions ofpersonal health threat or resource scarcity threat, either in the specific context of the COVID-19 pandemic or in general. We compared the threat manipulations to a relaxation manipulation designed to deactivate background threat perceptions as well as to a passive control condition. Confirmatory tests showed substantial activation of personal health and resourcescarcity threat perceptions. This brief technique can be easily used in online experiments. Distress due to the threat manipulation was rarely reported and easily managed with a debriefing toolkit.

Acute Effects of Handheld Vibration Massage on Posterior Shoulder Soft Tissues.

Interventions using vibration stimulation have been recognized for their potential for increasing range of motion (ROM) without compromising muscle strength. Handheld vibration massagers can efficiently deliver vibration therapy to the shoulder joint and may be a potential treatment. To evaluate the effects of vibration massage using a handheld device on the soft tissues of the posterior shoulder joint, particularly on internal rotation (IR) passive ROM and external rotation (ER) muscle strength. Crossover study design. A crossover study with a 5-min vibration massage and passive control condition was conducted in healthy male volunteers (mean age 20.5 ± 1.7 years). Vibration massage was applied to the posterior shoulder soft tissues of the dominant arm, with no intervention under control conditions. IR-ROM (vertebral level and in abduction) and strength of the external rotators (isometric and isokinetic) were measured before and immediately after the intervention. Vertebral levels were calculated as a ratio of lengths (ratio decreases with increased mobility). IR-ROM in abduction, the angle was measured. Statistical analysis was performed with two-way repeated measures ANOVA and paired t-test (Bonferroni correction). Vibration application decreased (improved) vertebral level IR ROM by -4.1% (p < 0.01, d = 0.445) and increased abduction position IR ROM by 11.4° (p < 0.01, d = 0.694). These changes exceeded the 95% confidence interval for the minimum detectable change. By contrast, the control condition produced no changes. IR-ROM (vertebral level and abduction) immediately after the intervention showed significant differences between the control and vibration conditions (p = 0.036, d = 0.273; p = 0.048, d = 0.483, respectively). Muscle strength did not show any interaction, time, or between-condition effects. A massage using a handheld vibration massager applied to the posterior shoulder soft tissues increased IR-ROM without negatively affecting muscle strength, suggesting its potential use as a means of warming up. Level 3.

Wireless passive condition monitoring system for aircraft

Wireless passive condition monitoring system for aircraft

Changes in Shoulder Rotation Based on Elevation in Children With Brachial Plexus Birth Injury

Lack of shoulder external rotation is common in children with brachial plexus birth injuries. Development of glenohumeral (GH) dysplasia is associated with progressive loss of passive external rotation. Some authors recommend measuring external rotation with the arm adducted, whereas others recommend measurement with the arm in 90° of abduction. The purpose of this study was to compare active and passive external rotation and internal rotation measured in adduction versus abduction. Fifteen children with brachial plexus birth injuries held their affected arms in maximal external and internal rotation with the arm adducted and the arm at approximately 90° of abduction. Active and passive rotations were measured with three-dimensional motion capture. Scapulothoracic (ST) internal/external rotation and GH internal/external rotation joint angles were calculated and compared using multivariable, one-way repeated measures analyses of variance. There were no significant differences for active or passive ST rotation in external rotation in adduction versus abduction. Glenohumeral external rotation was significantly increased with the arm in abduction compared with adduction both actively and passively. There were no differences in ST rotation in active versus passive conditions, but all GH rotations were significantly greater passively. Shoulder internal/external rotation in abduction and adduction is not interchangeable. Comprehensive assessment of shoulder external and internal rotation should include both adduction and abduction. For children with brachial plexus birth injuries, both active and passive GH external rotations were greater in abduction. Therefore, early GH joint dysplasia may be missed if GH external rotation is measured in abduction. Additionally, consistency in arm position is important for comparison over time. The entire ST rotation capacity was used to perform maximal internal and external rotation, but the entire passive GH range of motion was not actively used. This highlights an area for potential surgical intervention to improve motion.

Paraspinal Muscle Stiffness during Hamstring Exercise Using Shear-Wave Elastography.

Soccer teams integrate specific exercises into their typical workout programs for injury prevention. This study examined the effects of hamstring exercise on paraspinal and hamstring stiffness. These findings can inform training and rehabilitation programs to improve muscle health and prevent injuries. Fifteen young, healthy males performed passive and active (submaximal) knee flexion efforts from 0°, 45°, to 90° angle of knee flexion from the prone position. Using shear-wave elastography (SWE) and surface electromyography, we measured the elastic modulus and root mean square (RMS) signal of the erector spinae (ES), multifidus (MF), semitendinosus (ST), and semimembranosus (SM) during different knee flexion angles. Passive SWE modulus at 0° was 12.44 ± 4.45 kPa (ES), 13.35 ± 6.12 kPa (MF), 22.01 ± 4.68 kPa (ST), and 21.57 ± 5.22 kPa (SM) and it was greater (p < 0.05) compared to 45° and 90°. The corresponding values during knee flexion contractions at 0° increased to 18.99 ± 6.11 kPa (ES), 20.65 ± 11.31 kPa (MF), 71.21 ± 13.88 kPa (ST), and 70.20 ± 14.29 kPa (SM) and did not differ between angles (p > 0.05). Compared to rest, the relative increase in the SWE modulus during active contraction had a median value (interquartile range) ranging from 68.11 (86.29) to 101.69 (54.33)% for the paraspinal muscles and it was moderately to strongly correlated (r > 0.672) with the corresponding increase of the hamstring muscles [ranging from 225.94 (114.72) to 463.16 (185.16)%]. The RMS signal was greater during active compared to passive conditions, and it was lower at 90° compared to 45° (for SM/ST) and 0° (for all muscles). The association between paraspinal and hamstring passive muscle stiffness indicates a potential transmission of forces through myofascial connections between the lumbar spine and the lower limbs. In this laboratory setting, hamstring exercises affected the stiffness of the paraspinal muscles.

Real biofuel and fossil-fuel soot combustion activities in active and passive regeneration of diesel/gasoline particulate filters under different O2/NOx concentrations.

In this work, we aim to investigate and compare the combustion reactivities of real biofuel soot and fossil-fuel soot in the active and passive regeneration conditions of DPF and GPF through temperature-programmed oxidation (TPO). Higher reactivity of biofuel soot is achieved even under GPF conditions with extremely low oxygen concentration (~ 1%), which provides a great potential for low-temperature regeneration of GPF. Such a result is mainly attributed to the low graphitization and less surface C = C groups of biofuel soot. Unfortunately, the presence of high-content ashes (~ 47%) and P impurity in real biofuel soot hinder its combustion reactivity. TPO evidences that the O2/NOX-lacking conditions in GPF are key factors to impact the combustion of soot, especially fossil-fuel soot. This work provides some useful information for understanding real biofuel and fossil-fuel soot combustion in GPF and DPF regeneration and further improvement in filter regeneration process.

Amorphous silicon detectors for proton beam monitoring in FLASH radiotherapy

Ultra-high dose rate radiation therapy (FLASH) based on proton irradiation is of major interest for cancer treatments but creates new challenges for dose monitoring. Amorphous hydrogenated silicon is known to be one of the most radiation-hard semiconductors. In this study, detectors based on this material are investigated at proton dose rates similar to or exceeding those required for FLASH therapy. Tested detectors comprise two different types of contacts, two different thicknesses deposited either on glass or on polyimide substrates. All detectors exhibit excellent linear behaviour as a function of dose rate up to a value of 20 kGy/s. Linearity is achieved independently of the depletion condition of the device and remarkably in passive (unbiased) conditions. The degradation of the performance as a function of the dose rate and its recovery are also discussed.