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Scientific Reports Sep 2021The retrosplenial complex (RSC) plays a crucial role in spatial orientation by computing heading direction and translating between distinct spatial reference frames...
The retrosplenial complex (RSC) plays a crucial role in spatial orientation by computing heading direction and translating between distinct spatial reference frames based on multi-sensory information. While invasive studies allow investigating heading computation in moving animals, established non-invasive analyses of human brain dynamics are restricted to stationary setups. To investigate the role of the RSC in heading computation of actively moving humans, we used a Mobile Brain/Body Imaging approach synchronizing electroencephalography with motion capture and virtual reality. Data from physically rotating participants were contrasted with rotations based only on visual flow. During physical rotation, varying rotation velocities were accompanied by pronounced wide frequency band synchronization in RSC, the parietal and occipital cortices. In contrast, the visual flow rotation condition was associated with pronounced alpha band desynchronization, replicating previous findings in desktop navigation studies, and notably absent during physical rotation. These results suggest an involvement of the human RSC in heading computation based on visual, vestibular, and proprioceptive input and implicate revisiting traditional findings of alpha desynchronization in areas of the navigation network during spatial orientation in movement-restricted participants.
Topics: Adult; Alpha Rhythm; Female; Gyrus Cinguli; Head Movements; Humans; Occipital Lobe; Orientation, Spatial; Parietal Lobe; Rotation
PubMed: 34521939
DOI: 10.1038/s41598-021-97749-8 -
Biosensors Feb 2024The rotation of cells is of significant importance in various applications including bioimaging, biophysical analysis and microsurgery. Current methods usually require...
The rotation of cells is of significant importance in various applications including bioimaging, biophysical analysis and microsurgery. Current methods usually require complicated fabrication processes. Herein, we proposed an induced charged electroosmosis (ICEO) based on a chip manipulation method for rotating cells. Under an AC electric field, symmetric ICEO flow microvortexes formed above the electrode surface can be used to trap and rotate cells. We have discussed the impact of ICEO and dielectrophoresis (DEP) under the experimental conditions. The capabilities of our method have been tested by investigating the precise rotation of yeast cells and K562 cells in a controllable manner. By adjusting the position of cells, the rotation direction can be changed based on the asymmetric ICEO microvortexes via applying a gate voltage to the gate electrode. Additionally, by applying a pulsed signal instead of a continuous signal, we can also precisely and flexibly rotate cells in a stepwise way. Our ICEO-based rotational manipulation method is an easy to use, biocompatible and low-cost technique, allowing rotation regardless of optical, magnetic or acoustic properties of the sample.
Topics: Acoustics; Electricity; Electrodes; Electroosmosis; Rotation; Humans
PubMed: 38534219
DOI: 10.3390/bios14030112 -
Cortex; a Journal Devoted To the Study... Sep 2023Motor learning depends on the joint contribution of several processes including cognitive strategies aiming at goal achievement and prediction error-driven implicit...
Motor learning depends on the joint contribution of several processes including cognitive strategies aiming at goal achievement and prediction error-driven implicit adaptation. Understanding this functional interplay and its clinical implications requires insight into the individual learning processes, including at a neural level. Here, we set out to examine the impact of learning a cognitive strategy, over and above implicit adaptation, on the oscillatory post-movement β rebound (PMBR), which typically decreases in power following (visuo)motor perturbations. Healthy participants performed reaching movements towards a target, with online visual feedback replacing the view of their moving hand. The feedback was sometimes rotated, either relative to their movements (visuomotor rotation) or invariant to their movements (and relative to the target; clamped feedback), always for two consecutive trials interspersed between non-rotated trials. In both conditions, the first trial with a rotation was unpredictable. On the second trial, the task was either to re-aim, and thereby compensate for the rotation experienced in the first trial (visuomotor rotation; Compensate condition), or to ignore the rotation and keep on aiming at the target (clamped feedback; Ignore condition). After-effects did not differ between conditions, indicating that the amount of implicit learning was similar, while large differences in movement direction in the second rotated trial between conditions indicated that participants successfully acquired re-aiming strategies. Importantly, PMBR power following the first rotated trial was modulated differently in the two conditions. Specifically, it decreased in both conditions, but this effect was larger when participants had to acquire a cognitive strategy and prepare to re-aim. Our results therefore suggest that the PMBR is modulated by cognitive demands of motor learning, possibly reflecting the evaluation of a behaviourally significant goal achievement error.
Topics: Humans; Psychomotor Performance; Learning; Movement; Hand; Adaptation, Physiological; Feedback, Sensory; Rotation; Visual Perception
PubMed: 37295237
DOI: 10.1016/j.cortex.2023.05.002 -
Biophysical Journal May 2022Collective cell migration occurs in a wide range of physiological and pathological processes, such as wound healing and tumor metastasis. Experiments showed that many...
Collective cell migration occurs in a wide range of physiological and pathological processes, such as wound healing and tumor metastasis. Experiments showed that many types of cells confined in circular islands can perform coherent angular rotation, yet the underlying mechanisms remain unclear. Here we propose a biomechanical model, including the membrane, microtubules, and nucleus, to study the spatiotemporal evolutions of small cell clusters in confined space. We show that cells can spontaneously transfer from "radial pattern" to "chiral pattern" due to fluctuations. For a pair of cells with identical chiral orientation, the cluster rotates in the opposite direction of the chiral orientation, and the fluctuations can reverse the cluster's rotational direction. Interestingly, during the persistent rotation, each cell rotates around its own centroid while it is revolving around the island center and shows a constant side to the island center, as tidal locking in astronomy. Furthermore, for a few more cells, coherent angular rotation also appears, and the emergence of a central cell can accelerate the cluster rotation. These findings shed light on collective cell migration in life processes and help to understand the spatiotemporal dynamics of active matter.
Topics: Cell Movement; Microtubules; Models, Biological; Rotation; Wound Healing
PubMed: 35398343
DOI: 10.1016/j.bpj.2022.04.011 -
Scientific Reports Apr 2022Lophotrichous bacteria swim through fluid by rotating their flagellar bundle extended collectively from one pole of the cell body. Cells experience modes of motility...
Lophotrichous bacteria swim through fluid by rotating their flagellar bundle extended collectively from one pole of the cell body. Cells experience modes of motility such as push, pull, and wrapping, accompanied by pauses of motor rotation in between. We present a mathematical model of a lophotrichous bacterium and investigate the hydrodynamic interaction of cells to understand their swimming mechanism. We classify the swimming modes which vary depending on the bending modulus of the hook and the magnitude of applied torques on the motor. Given the hook's bending modulus, we find that there exist corresponding critical thresholds of the magnitude of applied torques that separate wrapping from pull in CW motor rotation, and overwhirling from push in CCW motor rotation, respectively. We also investigate reoriented directions of cells in three-dimensional perspectives as the cell experiences different series of swimming modes. Our simulations show that the transition from a wrapping mode to a push mode and pauses in between are key factors to determine a new path and that the reoriented direction depends upon the start time and duration of the pauses. It is also shown that the wrapping mode may help a cell to escape from the region where the cell is trapped near a wall.
Topics: Bacteria; Flagella; Hydrodynamics; Movement; Rotation; Swimming
PubMed: 35444244
DOI: 10.1038/s41598-022-09823-4 -
The Knee Mar 2014Dynamic knee valgus contributes to injuries of the anterior cruciate ligament (ACL). However, it is unclear how the knee rotates during dynamic knee valgus. Knee...
BACKGROUND
Dynamic knee valgus contributes to injuries of the anterior cruciate ligament (ACL). However, it is unclear how the knee rotates during dynamic knee valgus. Knee rotation significantly affects ACL strain. To understand knee rotation during dynamic knee valgus should help the clinician evaluate dynamic alignment. The purpose of this study was to determine how the knee rotates during dynamic knee valgus and whether the knee rotation is affected by toe direction (foot rotation).
METHODS
Sixteen females performed dynamic knee valgus in three toe directions (neutral, toe-out, and toe-in) while maintaining the knee flexion angle at 30°. The knee rotation angle was evaluated using a 7-camera motion analysis system. Knee rotation was compared between the start position and the dynamic knee valgus position, as well as among the three toe directions, using repeated measures ANOVA models.
RESULTS
The knee significantly rotated externally in the dynamic knee valgus position compared with the start position in two toe directions (neutral and toe-out). A similar tendency was observed with the toe-in condition. Toe direction significantly affected the knee rotation angle. For toe-out and toe-in conditions, external and internal shifts of knee rotation compared with neutral were observed.
CONCLUSIONS
The knee rotates externally during dynamic knee valgus, and the knee rotation is affected by toe direction.
CLINICAL RELEVANCE
Because of knee abduction and external rotation, the ACL may impinge on the femoral condyle in the case of dynamic valgus, especially in the toe-out position.
Topics: Analysis of Variance; Biomechanical Phenomena; Female; Foot; Humans; Knee Joint; Rotation; Young Adult
PubMed: 23290175
DOI: 10.1016/j.knee.2012.12.002 -
Biophysical Journal Jun 2018Intracellular cargos are transported by molecular motors along actin and microtubules, but how their dynamics depends on the complex structure of the cytoskeletal...
Intracellular cargos are transported by molecular motors along actin and microtubules, but how their dynamics depends on the complex structure of the cytoskeletal network remains unclear. In this study, we investigated this longstanding question by measuring simultaneously the rotational and translational dynamics of cargos at microtubule intersections in living cells. We engineered two-faced particles that are fluorescent on one hemisphere and opaque on the other and used their optical anisotropy to report the rotation of cargos. We show that cargos undergo brief episodes of unidirectional and rapid rotation while pausing at microtubule intersections. Probability and amplitude of the cargo rotation depend on the geometry of the intersecting filaments. The cargo rotation is not random motion due to detachment from microtubules, as revealed by statistical analyses of the translational and rotational dynamics. Instead, it is an active rotation driven by motor proteins. Although cargos are known to pause at microtubule intersections, this study reveals a different dimension of dynamics at this seemingly static state and, more importantly, provides direct evidence showing the correlation between cargo rotation and the geometry of underlying microtubule intersections.
Topics: Animals; Cell Survival; Chlorocebus aethiops; Intracellular Space; Kinesins; Microtubules; Movement; Rotation; Vero Cells
PubMed: 29925026
DOI: 10.1016/j.bpj.2018.05.010 -
Biophysical Journal Aug 2022Chirality is a common and essential characteristic at varied scales of living organisms. By adapting the rotational clutch-filament model we previously developed, we...
Chirality is a common and essential characteristic at varied scales of living organisms. By adapting the rotational clutch-filament model we previously developed, we investigate the effect of torque relaxation of a formin on cellular chiral swirling. Since it is still unclear how the torque on a formin is exactly relaxed, we probe three types of torque relaxation, as suggested in the literature. Our analysis indicates that, when a formin periodically undergoes positive and negative rotation during processive capping to relax the torque, cells hardly rotate. When the switch between the positive and the negative rotation during the processive capping is randomly regulated by the torque, our analysis indicates that cells can only slightly rotate either counterclockwise or clockwise. When a formin relaxes the torque by transiently loosening its contact either with the membrane at its anchored site or with the actin filament, we find that cells can prominently rotate either counterclockwise or clockwise, in good consistency with the experiment. Thus, our studies indicate that how the torque on a formin is relaxed strongly affects cellular swirling and suggest an efficient type of torque relaxation in switching cellular swirling.
Topics: Actin Cytoskeleton; Actins; Formins; Rotation; Torque
PubMed: 35773996
DOI: 10.1016/j.bpj.2022.06.027 -
International Journal of Molecular... Dec 2023We review experimental results obtained with broadband dielectric spectroscopy concerning the relaxation times and activation energies of intramolecular conformational... (Review)
Review
We review experimental results obtained with broadband dielectric spectroscopy concerning the relaxation times and activation energies of intramolecular conformational relaxation processes in small-molecule glass-formers. Such processes are due to the interconversion between different conformers of relatively flexible molecules, and generally involve conformational changes of flexible chain or ring moieties, or else the rigid rotation of planar groups, such as conjugated phenyl rings. Comparative analysis of molecules possessing the same (type of) functional group is carried out in order to test the possibility of assigning the dynamic conformational isomerism of given families of organic compounds to the motion of specific molecular subunits. These range from terminal halomethyl and acetyl/acetoxy groups to both rigid and flexible ring structures, such as the planar halobenzene cycles or the buckled saccharide and diazepine rings. A short section on polyesters provides a generalisation of these findings to synthetic macromolecules.
Topics: Dielectric Spectroscopy; Molecular Conformation; Rotation
PubMed: 38139017
DOI: 10.3390/ijms242417189 -
International Journal of Clinical... Oct 2023Pharmacists are vital to optimizing therapy of people with mental illnesses. Limited knowledge, lack of confidence, and mental health-related stigma can lead to... (Review)
Review
BACKGROUND
Pharmacists are vital to optimizing therapy of people with mental illnesses. Limited knowledge, lack of confidence, and mental health-related stigma can lead to pharmacists' reluctance in the provision of pharmaceutical care to this population. Advanced pharmacy practice experiences (APPE) in mental health have been reported as valuable learning opportunities to overcome these challenges.
AIM
This study aimed to explore PharmD graduates' perceived preparedness, attitudes, beliefs, and opinions on influencing factors for the provision of pharmaceutical care to people with mental illnesses after completing an APPE rotation in psychiatry.
METHOD
All PharmD graduates who had completed a rotation in psychiatry were invited to participate in semi-structured interviews. An interview guide was developed based on a literature review. A total of 11 PharmD graduates agreed to participate in the interviews, which were recorded, transcribed, and analysed inductively using thematic analysis and following a phenomenological approach.
RESULTS
Five themes were identified: Prior familiarity to mental health, opinions on the rotation, views on stigma, rotation's areas of improvement, and the positive impact of the rotation on practice. Although participants started the psychiatric rotation with low confidence and a sense of apprehension, they described their experience as unique, eye-opening, and insightful. Familiarity with mental health conditions before the rotation were perceived as a challenge to achieving full confidence in mental health care provision.
CONCLUSION
For the most part, the APPE in psychiatry was viewed as a positive opportunity for enhancing the PharmD graduates' insight, knowledge, and skills for pharmaceutical care provision to people with mental illnesses.
Topics: Humans; Rotation; Mental Disorders; Pharmaceutical Services; Pharmacy; Pharmacists; Psychiatry
PubMed: 37796362
DOI: 10.1007/s11096-023-01646-1