Movement Onset Research Articles

Anion and cation dynamics in a carbon-substituted cesium closo-hydroborate CsCB11H12: 1H and 133Cs NMR studies

Cesium monocarba-hydroborate CsCB11H12 belongs to the family of alkali-metal closo- hydroborate salts which are considered as promising solid electrolytes for battery applications. To study the dynamical properties of this compound at the microscopic level, we have measured the 1H and 133Cs nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation rates over the temperature range of 80–434 K. Our measurements have revealed a coexistence of two types of reorientational jump processes of the complex [CB11H12]− anions. For the faster of these processes characterized by the average activation energy of 310 meV, the anion reorientations are not “frozen” at the NMR frequency scale down to 120 K. The behavior of the 133Cs NMR line width in CsCB11H12 is consistent with the onset of long-range diffusive motion of Cs+ ions at the frequency scale of ∼104 s−1 above 340 K, and the distinct effects of the diffusive Cs+ jumps on both the 1H and 133Cs spin-lattice relaxation rates become observable above 380 K.

Three-dimensional numerical modeling of ground motion in the Valley of Mexico: A case study from the Mw3.2 earthquake of July 17, 2019

In this study, a 3D physics-based numerical approach, based on the spectral element numerical code SPEED, is used to simulate seismic wave propagation due to a local earthquake in the Mexico City area. The availability of detailed geological, geophysical, geotechnical, and seismological data allowed for the creation of a large-scale (60 km × 60 km in plan, 10 km in depth) heterogeneous 3D numerical model of the Mexico City area, dimensioned to accurately propagate frequencies up to about 1.3 Hz. The results of numerical simulations are validated against the ground motion recordings of the July 17, 2019, Mw3.2 earthquake, with peak ground acceleration exceeding 0.3 g about 1 km away from the epicenter. A good agreement with records is found, quantitatively evaluated through goodness-of-fit checks. Furthermore, for the lake zone, the simulated decay trend of the peak ground velocity with epicentral distance is reasonably close to the observations, for both horizontal and vertical components. In spite of some limitations, the simulations are successful to provide a realistic picture of seismic wave propagation both in the hill and in the lake zones of Mexico City, including the onset of long-duration quasi-monochromatic ground motion in the basin, with strong amplification at low frequencies (between 0.4 and 0.7 Hz). The numerical results also suggest that surface waves, with predominant prograde particle motion at the ground surface and large ellipticities, dominate the wavefield in the lake zone. Based on these positive outcomes, we conclude that this numerical model may be useful for both a better insight into the seismic response of the Valley of Mexico and the simulation of ground motions during larger-magnitude earthquakes, to generate improved seismic damage scenarios in Mexico City.

Synchronization in collectively moving inanimate and living active matter

Whether one considers swarming insects, flocking birds, or bacterial colonies, collective motion arises from the coordination of individuals and entails the adjustment of their respective velocities. In particular, in close confinements, such as those encountered by dense cell populations during development or regeneration, collective migration can only arise coordinately. Yet, how individuals unify their velocities is often not understood. Focusing on a finite number of cells in circular confinements, we identify waves of polymerizing actin that function as a pacemaker governing the speed of individual cells. We show that the onset of collective motion coincides with the synchronization of the wave nucleation frequencies across the population. Employing a simpler and more readily accessible mechanical model system of active spheres, we identify the synchronization of the individuals’ internal oscillators as one of the essential requirements to reach the corresponding collective state. The mechanical ‘toy’ experiment illustrates that the global synchronous state is achieved by nearest neighbor coupling. We suggest by analogy that local coupling and the synchronization of actin waves are essential for the emergent, self-organized motion of cell collectives.

Effects of chronic caffeine on patterns of brain blood flow and behavior throughout the sleep-wake cycle in freely behaving mice.

Caffeine has significant effects on neurovascular activity and behavior throughout the sleep-wake cycle. We used a minimally invasive microchip/video system to continuously record effects of caffeine in the drinking water of freely behaving mice. Chronic caffeine shifted both rest and active phases by up to 2 h relative to the light-dark cycle in a dose-dependent fashion. There was a particular delay in the onset of rapid eye movement (REM) sleep as compared with non-REM sleep during the rest phase. Chronic caffeine increased wakefulness during the active phase and consolidated sleep during the rest phase; overall, there was no net change in the amount of time spent in the wake, sleep, or REM sleep states during caffeine administration. Despite these effects on wakefulness and sleep, chronic caffeine decreased mean cerebral blood volume (CBV) during the active phase and increased mean CBV during the rest phase. Chronic caffeine also increased heart rate variability in both the sleep and wake states. These results provide new insight into the effects of caffeine on the biology of the sleep-wake cycle. Increased blood flow during sleep caused by chronic caffeine may have implications for its potential neuroprotective effects through vascular mechanisms of brain waste clearance.

Transformation of Pluripotency States during Morphogenesis of Mouse and Human Epiblast

The pluripotent status of a cell in vivo is spatio-temporally regulated within embryogenesis and is determined by the processes of self-renewal, endless proliferation and differentiation into all cell types of the body. Previously, the pluripotency was characterized using teratocarcinoma cells. Then this term was applied to the embryonic cells of the preimplantation mouse embryo. Preimplantationally formed mouse and human pluripotent stem cells (PSCs) appear to exist until gastrulation. One of the main events in the early mammalian development is the differentiation of the inner cell mass of the blastocyst (ICM) into a hypoblast and an epiblast, which develops into the embryo itself. Continuous and dynamic transformation of pluripotency states in development coincides with the morphogenetic processes, which are involved in the formation and maturation of the epiblast. Thus, blastocyst ICM cells differ in epigenetic and transcription patterns from their daughter cells forming the peri/post-implantation epiblast. With the onset of gastrulation movements, the maturation of epiblast cells ends with their differentiation into cells of three germ layers. This review considers the historical aspects of the study of cell pluripotency, various sources of PSCs, mechanisms and signaling pathways that support self-renewal and pluripotency in PSC cultures. In addition, we summarize and conceptualize data on morphogenetic processes that are involved in the formation of naive ICM cells in vivo and the subsequent maturation of mouse and human epiblast cells associated with the transformation of their pluripotency states.

How thresholding in segmentation affects the regression performance of the linear model.

Evaluating any model underlying the control of speech requires segmenting the continuous flow of speech effectors into sequences of movements. A virtually universal practice in this segmentation is to use a velocity-based threshold which identifies a movement onset or offset as the time at which the velocity of the relevant effector breaches some threshold percentage of the maximal velocity. Depending on the threshold choice, more or less of the movement's trajectory is left in for model regression. This paper makes explicit how the choice of this threshold modulates the regression performance of a dynamical model hypothesized to govern speech movements.

A motor plan is accessible for voluntary initiation and involuntary triggering at similar short latencies.

Movement goals are an essential component of motor planning, altering voluntary and involuntary motor actions. While there have been many studies of motor planning, it is unclear if motor goals influence voluntary and involuntary movements at similar latencies. The objectives of this study were to determine how long it takes to prepare a motor action and to compare this time for voluntary and involuntary movements. We hypothesized a prepared motor action would influence voluntarily and involuntarily initiated movements at the same latency. We trained subjects to reach with a forced reaction time paradigm and used a startling acoustic stimulus (SAS) to trigger involuntary initiation of the same reaches. The time available to prepare was controlled by varying when one of four reach targets was presented. Reach direction was used to evaluate accuracy. We quantified the time between target presentation and the cue or trigger for movement initiation. We found that reaches were accurately initiated when the target was presented 48ms before the SAS and 162ms before the cue to voluntarily initiate movement. While the SAS precisely controlled the latency of movement onset, voluntary reach onset was more variable. We, therefore, quantified the time between target presentation and movement onset and found no significant difference in the time required to plan reaches initiated voluntarily or involuntarily (∆ = 8ms, p = 0.2). These results demonstrate that the time required to plan accurate reaches is similar regardless of if they are initiated voluntarily or triggered involuntarily. This finding may inform the understanding of neural pathways governing storage and access of motor plans.

Direction and distance dependency of reaching movements of lower limb.

Efficient body movement is required in our daily lives, as it facilitates responding to the external environment and producing movements in various directions and distances. While numerous studies have reported on goal-directed movements in the frontal direction during gait initiation, there is limited research on the efficient movement of the lower limbs in multiple directions and distances. Therefore, we aimed to examine changes in the kinematics of lower-limb reaching movements to determine skilled motor ability in terms of direction and distance. Sixteen adults (10 male participants) were requested to reach targets projected on the floor in seven directions and at three distances for a total of 21 points. The reaching time slowed down for the contralateral side (right foot to left-sided target) and was caused by a slower start of the toe movement. To identify the cause of this delay, we analyzed the onset of movement at each joint and found that movement to the contralateral side starts from the hip, followed by the knee, and subsequently the toe. The time-to-peak velocity was also calculated, and the motion required to reach the target in the shortest time varied depending on direction and distance. These results suggested that movement kinematics vary with direction and distance, resulting in a slower reaching time on the contralateral side. The results of our study hold promise for potential applications in sports and rehabilitation.

The Reason for the Rise in Critical Shear Stress on Sloping Beds

In sediment mechanics, the conditions for the onset of sediment movement are of particular importance. However, despite decades of research, questions remain unanswered. Thus, physical logic suggests that sediments move more easily on beds inclined in the direction of flow than on horizontal beds and that transport rates are correspondingly increased. However, numerous studies have shown that sediments require increased rather than decreased shear stress to move on sloping beds and that transport rates are lower instead of increased. Since an early publication on this issue by Ashida and Michiue in 1973, many possible effects have been suggested for this apparent contradiction. The literature almost consistently concludes that high relative roughness (d/h), i.e., low water cover (h/d), is mainly responsible for this contradictory effect. This is true for current-induced sediment transport and for the initiation of debris flow. In this paper, an analytical solution for the effect of small water coverage on the transport process is developed. Effects of low coverage also occur on beaches during wave runup and runoff and thus control the formation of steep or less steep beaches. The present paper shows that the effect of turbulence damping occurring under low water coverage plays a decisive role here.

Mechanical force regulates Sox9 expression at the developing enthesis.

Entheses transmit force from tendons and ligaments to the skeleton. Regional organization of enthesis extracellular matrix (ECM) generates differences in stiffness required for force transmission. Two key transcription factors co-expressed in entheseal tenocytes, scleraxis (Scx) and Sox9, directly control production of enthesis ECM components. Formation of embryonic craniofacial entheses in zebrafish coincides with onset of jaw movements, possibly in response to the force of muscle contraction. We show dynamic changes in scxa and sox9a mRNA levels in subsets of entheseal tenocytes that correlate with their roles in force transmission. We also show that transcription of a direct target of Scxa, Col1a, in enthesis ECM is regulated by the ratio of scxa to sox9a expression. Eliminating muscle contraction by paralyzing embryos during early stages of musculoskeletal differentiation alters relative levels of scxa and sox9a in entheses, primarily owing to increased sox9a expression. Force-dependent TGF-β (TGFβ) signaling is required to maintain this balance of scxa and sox9a expression. Thus, force from muscle contraction helps establish a balance of transcription factor expression that controls specialized ECM organization at the tendon enthesis and its ability to transmit force.

Acquired alterations in nucleus accumbens responsiveness to a cocaine-paired discriminative stimulus preceding rats’ daily cocaine consumption

Resumption of drug taking is a primary focus for substance use disorder research and can be triggered by drug-associated environmental stimuli. The Nucleus Accumbens (NAc) is a key brain region which guides motivated behavior and is implicated in resumption. Yet, there remains a pressing need to characterize NAc neurons’ responsiveness to drug associated stimuli during withdrawal and abstinence. We recorded discriminative stimulus (DS) induced NAc activity via in vivo single-unit electrophysiology in rats that self-administered cocaine. Male and female rats implanted with a jugular catheter and a microwire array in NAc Core and Shell self-administered cocaine under control of a 30s auditory DS for 6 hours per session across 14 consecutive days. Rats acquired tone discrimination within 4 sessions. To exclude pharmacological effects of circulating cocaine from all neuronal analyses, we studied changes in DS-induced firing only for trials preceding the first infusion of cocaine in each of the 14 sessions, which were defined as “pre-drug trials.” NAc neuron responses were assessed prior to tone-evoked movement onset. Responsiveness to the DS tone was exhibited throughout all sessions by the NAc Core population, but only during Early sessions by the NAc Shell population. Both Core and Shell responded selectively to the DS, i.e., more strongly on drug taking trials, or Hits, than on Missed opportunities. These findings suggest that NAc Core and Shell play distinct roles in initiating cocaine seeking prior to daily cocaine consumption, and align with reports suggesting that as drug use becomes chronic, cue-evoked activity shifts from NAc Shell to NAc Core.

Evaluation of airlift pump performance for vertical conveying of coal particles

AbstractOne of the crucial aspects of reducing air consumption when conveying particles with an airlift pump is to know the factors that affect the process of particle motion at an initial velocity of zero. To determine the influence of submergence ratio and physical properties of particles (such as size, shape, and mass) on the onset of vertical particle motion, the airlift pump was taken as the research object, and spherical glass together with irregular shaped coal were used as experimental test particles. The results show that unlike the water-solid environment, the start of particle motion in the water-air mixture does not always occur at a certain value of superficial water velocity and this value also increases with increasing submergence level. Among the parameters considered, the role of submergence ratio is much more effective than the dimensions and the shape of the particle, because by increasing submergence from 0.3 to 0.8, it is possible to reduce air consumption by up to 8 times. Based on this study the corresponding theoretical model derived by Fujimoto et al. is optimized, wherein the overall agreement between the modified theory and present experimental data is particularly good. Contrary to Fujimoto, the minimum superficial water velocity for lifting solids in the air-water mixture is not always smaller than water ambient which indicates on optimum submergence ratio higher than 0.7. Finally, a new criterion was introduced to describe the moment of onset of the particle motion as a function of the superficial fluid velocity ratio for each submergence value.

Domain wall motion at low current density in a synthetic antiferromagnet nanowire

The current-driven motion of magnetic domain walls (DWs) is the working principle of magnetic racetrack memories. In this type of spintronic technology, high current densities are used to propel DW motion in magnetic nanowires, causing significant wire heating that corresponds to wasted energy. Synthetic antiferromagnets are known to show very fast DW motion at high current densities, but lower current densities around onset of motion have received less attention. Here we use scanning transmission x-ray microscopy to study the response of DWs in a SAF multilayer to short current pulses. We observe that the DWs depin at A m−2 and move more quickly in response to 5 ns duration current pulses than in comparable multilayers that lack antiferromagnetic coupling. The results suggest that DWs in SAF structures are superior to conventional Néel DWs for low energy consumption racetrack technologies.

The archerfish predictive C-start.

A very quick decision enables hunting archerfish to secure downed prey even when they are heavily outnumbered by competing other surface-feeding fish. Based exclusively on information that is taken briefly after the onset of prey motion, the fish select a rapid C-start that turns them right towards the later point of catch. Moreover, the C-start, and not later fin strokes, already lends the fish the speed needed to arrive at just the right time. The archerfish predictive C-starts are kinematically not distinguishable from escape C-starts made by the same individual and are among the fastest C-starts known in teleost fish. The start decisions allow the fish-for ballistically falling prey-to respond accurately to any combination of the initial variables of prey movement and for any position and orientation of the responding fish. The start decisions do not show a speed-accuracy tradeoff and their accuracy is buffered against substantial changes of environmental parameters. Here, I introduce key aspects of this high-speed decision that combines speed, complexity, and precision in an unusual way.

Stimulus Onset Asynchrony Affects Weighting-related Event-related Spectral Power in Self-motion Perception.

Self-motion perception relies primarily on the integration of the visual, vestibular, proprioceptive, and somatosensory systems. There is a gap in understanding how a temporal lag between visual and vestibular motion cues affects visual-vestibular weighting during self-motion perception. The beta band is an index of visual-vestibular weighting, in that robust beta event-related synchronization (ERS) is associated with visual weighting bias, and robust beta event-related desynchronization is associated with vestibular weighting bias. The present study examined modulation of event-related spectral power during a heading judgment task in which participants attended to either visual (optic flow) or physical (inertial cues stimulating the vestibular, proprioceptive and somatosensory systems) motion cues from a motion simulator mounted on a MOOG Stewart Platform. The temporal lag between the onset of visual and physical motion cues was manipulated to produce three lag conditions: simultaneous onset, visual before physical motion onset, and physical before visual motion onset. There were two main findings. First, we demonstrated that when the attended motion cue was presented before an ignored cue, the power of beta associated with the attended modality was greater than when visual-vestibular cues were presented simultaneously or when the ignored cue was presented first. This was the case for beta ERS when the visual-motion cue was attended to, and beta event-related desynchronization when the physical-motion cue was attended to. Second, we tested whether the power of feature-binding gamma ERS (demonstrated in audiovisual and visual-tactile integration studies) increased when the visual-vestibular cues were presented simultaneously versus with temporal asynchrony. We did not observe an increase in gamma ERS when cues were presented simultaneously, suggesting that electrophysiological markers of visual-vestibular binding differ from markers of audiovisual and visual-tactile integration. All event-related spectral power reported in this study were generated from dipoles projecting from the left and right motor areas, based on the results of Measure Projection Analysis.

Ocular following responses of the marmoset monkey are dependent on postsaccadic delay, spatiotemporal frequency, and saccade direction.

Ocular following is a short-latency, reflexive eye movement that tracks wide-field visual motion. It has been studied extensively in humans and macaques and is an appealing behavior for studying sensory-motor transformations in the brain because of its rapidity and rigidity. We explored ocular following in the marmoset, an emerging model in neuroscience because their lissencephalic brain allows direct access to most cortical areas for imaging and electrophysiological recordings. In three experiments, we tested ocular following responses in three adult marmosets. First, we varied the delay between saccade end and stimulus motion onset, from 10 to 300 ms. As in other species, tracking had shorter onset latencies and higher eye speeds with shorter postsaccadic delays. Second, using sine-wave grating stimuli, we explored the dependence of eye speed on spatiotemporal frequency. The highest eye speed was evoked at ∼16 Hz and ∼0.16 cycles per degree (cpd); however, the highest gain was elicited at ∼1.6 Hz and ∼1.2 cpd. The highest eye speed for each spatial frequency was observed at a different temporal frequency, but this interdependence was not consistent with complete speed tuning of the ocular following response. Finally, we found the highest eye speeds when saccade and stimulus motion directions were identical, although latencies were unaffected by direction difference. Our results showed qualitatively similar ocular following in marmosets, humans, and macaques, despite over an order of magnitude variation in body and eye size across species. This characterization will help future studies examining the neural basis of sensory-motor transformations.NEW & NOTEWORTHY Previous ocular following studies focused on humans and macaques. We examined the properties of ocular following responses in marmosets in three experiments, in which postsaccadic delay, spatial-temporal frequency of stimuli, and congruence of saccade and motion directions were manipulated. We have demonstrated short-latency ocular following in marmosets and discuss the similarities across three species that vary markedly in eye and head size. Our findings will help future studies examining the neural mechanism of sensory-motor transformations.

Employing novel wireless agricultural sensors for real‐time monitoring of fluvial bank erosion

AbstractBank erosion impacts sediment transport and river morphology, both important processes for river managers. Some important factors, such as timing and causes of bank erosion, are difficult to assess with established techniques. We explore the capability of smart sensors, actually developed for the agricultural sector, to measure soil moisture and temperature as well as movement in real time on banks of northern rivers in different geographical, climatological and landscape settings. Soil movement and its timing were easy to identify from the measurements, and in many cases, the reason for the onset of movement could be inferred. The sensors automatically upload data with a high temporal resolution for a long period of time, while only minimally disturbing the bank itself. However, the sensor approach has a low spatial resolution (point measurements), and therefore, complementing the measurements with approaches with a high spatial resolution, such as spatially continuous digital elevation models of differencing techniques or seismic sensors, is advised. Overall, the measurement approach using new agricultural sensors has several unique advantages and disadvantages and can be a good tool for the monitoring of river bank erosion and could lead to new insights.

Eight-and-a-half syndrome in a patient with hypertensive emergencies.

An 88-year-old white female was admitted with a hypertensive emergency and a sudden onset of abnormal extraocular movements and facial (cranial nerve VII) palsy. This article presents a case of the eight-and-a-half syndrome and discusses its underlying etiology. The patient's unique clinical presentation at the time of admission was correctly identified, leading to the correct diagnosis. Finally, the article provides a review of the neuroanatomy related to the lesion causing the eight-and-a-half syndrome in this patient.

The correlation between strength and range of motion of the neck muscles and opium smoking in Iran.

Opium smoking is commonly practiced via traditional and novel routes in Iran. Both smoking methods are practiced in a non-ergonomic position. According to previous studies and our hypothesis, it can be potentially harmful to the cervical spine. Thus, the present study aimed to investigate the relationship between opium smoking and neck range of motion and neck muscle strength. In this cross-sectional and correlational study, the range of motion and strength of the neck muscles of 120 men with drug use disorder were measured by a CROM goniometer and a hand-held dynamometer. Other data gathering was performed using a demographic questionnaire, the Maudsley Addiction Profile, and the Persian version of Leeds Dependence Questionnaire. The obtained data were analyzed by Shapiro-Wilks test, Pearson's correlation coefficient and stepwise linear regression. There was no significant correlation between the age of drug use onset and range of motion and muscle strength of the neck; however, the daily duration of opium smoking and the number of years of opium smoking were inversely and significantly correlated with the range of motion and muscle strength of the neck in some directions. Daily opium smoking time for decreasing in neck range of motion and total duration of opium smoking for reduction of neck muscles strength are stronger predictor variables. Opium smoking by traditional routes causes non-ergonomic positions and has a moderate significant correlation with reduced range of motion and neck muscle strength, in Iran. - The harm of drug use disorder is not only AIDS and hepatitis, and harm reduction programs should go beyond the prevention of AIDS and hepatitis. According to more than 90% of smoking use of drug compared to other methods (oral and injectable, etc.) musculoskeletal disorders caused by the smoking use of drugs, have a greater cost burden in reducing the quality of life and the need for rehabilitation.- Drug abuse treatment and harm reduction programs should focus more seriously on replacing smoking use of drugs with oral medications assisted treatment.- Although in Iran and some countries in the region, a large number of people smoke opium for many years and sometimes all their lives, daily in a completely non-ergonomic position, but studying the deformation of the posture and musculoskeletal disorders related to the body position in them, is not a scientific concern and neither physical therapy researchers have paid attention to it nor addiction researchers.- Neck muscles strength and range of motion in opium addicts are correlated to the number of years of opium smoking and daily minutes of opium smoking, but not to its oral use.- There is no significant correlation between the onset age of continues and permanent opium smoking and substance dependence severity with neck range of motion and muscles strength.- People with drug use disorder (especially smoking users) as a large group of vulnerable people, should be the target population of musculoskeletal disorders researchers and addiction harm reduction researchers, and more experimental, comparative, cohort, etc. researches should be designed and implemented for them.

Fast-Spiking Interneurons of the Premotor Cortex Contribute to Initiation and Execution of Spontaneous Actions.

Planning and execution of voluntary movement depend on the contribution of distinct classes of neurons in primary motor and premotor areas. However, timing and pattern of activation of GABAergic cells during specific motor behaviors remain only partly understood. Here, we directly compared the response properties of putative pyramidal neurons (PNs) and GABAergic fast-spiking neurons (FSNs) during spontaneous licking and forelimb movements in male mice. Recordings centered on the face/mouth motor field of the anterolateral motor cortex (ALM) revealed that FSNs fire longer than PNs and earlier for licking, but not for forelimb movements. Computational analysis revealed that FSNs carry vastly more information than PNs about the onset of movement. While PNs differently modulate their discharge during distinct motor acts, most FSNs respond with a stereotyped increase in firing rate. Accordingly, the informational redundancy was greater among FSNs than PNs. Finally, optogenetic silencing of a subset of FSNs reduced spontaneous licking movement. These data suggest that a global rise of inhibition contributes to the initiation and execution of spontaneous motor actions.SIGNIFICANCE STATEMENT Our study contributes to clarifying the causal role of fast-spiking neurons (FSNs) in driving initiation and execution of specific, spontaneous movements. Within the face/mouth motor field of mice premotor cortex, FSNs fire before pyramidal neurons (PNs) with a specific activation pattern: they reach their peak of activity earlier than PNs during the initiation of licking, but not of forelimb, movements; duration of FSNs activity is also greater and exhibits less selectivity for the movement type, as compared with that of PNs. Accordingly, FSNs appear to carry more redundant information than PNs. Optogenetic silencing of FSNs reduced spontaneous licking movement, suggesting that FSNs contribute to the initiation and execution of specific spontaneous movements, possibly by sculpting response selectivity of nearby PNs.