Stimulus Direction Research Articles

Temporally and functionally distinct large-scale brain network dynamics supporting task switching

ObjectiveOur daily activities require frequent switches among competing responses at the millisecond time scale. We determined the spatiotemporal characteristics and functional significance of rapid, large-scale brain network dynamics during task switching. MethodsThis cross-sectional study investigated patients with drug-resistant focal epilepsy who played a Lumosity cognitive flexibility training game during intracranial electroencephalography (iEEG) recording. According to a given task rule, unpredictably switching across trials, participants had to swipe the screen in the direction the stimulus was pointing or moving. Using this data, we described the spatiotemporal characteristics of iEEG high-gamma augmentation occurring more intensely during switch than repeat trials, unattributable to the effect of task rule (pointing or moving), within-stimulus congruence (the direction of stimulus pointing and moving was same or different in a given trial), or accuracy of an immediately preceding response. Diffusion-weighted imaging (DWI) tractography determined whether distant cortical regions showing enhanced activation during task switch trials were directly connected by white matter tracts. Trial-by-trial iEEG analysis deduced whether the intensity of task switch-related high-gamma augmentation was altered through practice and whether high-gamma amplitude predicted the accuracy of an upcoming response among switch trials. ResultsThe average number of completed trials during five-minute gameplay was 221.4 per patient (range: 171–285). Task switch trials increased the response times, whereas later trials reduced them. Analysis of iEEG signals sampled from 860 brain sites effectively elucidated the distinct spatiotemporal characteristics of task switch, task rule, and post-error-specific high-gamma modulations. Post-cue, task switch-related high-gamma augmentation was initiated in the right calcarine cortex after 260 ms, right precuneus after 330 ms, right entorhinal after 420 ms, and bilateral anterior middle-frontal gyri after 450 ms. DWI tractography successfully showed the presence of direct white matter tracts connecting the right visual areas to the precuneus and anterior middle-frontal regions but not between the right precuneus and anterior middle-frontal regions. Task-related high-gamma amplitudes in later trials were reduced in the calcarine, entorhinal and anterior middle-frontal regions, but increased in the precuneus. Functionally, enhanced post-cue precuneus high-gamma augmentation improved the accuracy of subsequent responses among switch trials. ConclusionsOur multimodal analysis uncovered two temporally and functionally distinct network dynamics supporting task switching. High-gamma augmentation in the visual-precuneus pathway may reflect the neural process facilitating an attentional shift to a given updated task rule. High-gamma activity in the visual-dorsolateral prefrontal pathway, rapidly reduced through practice, may reflect the cost of executing appropriate stimulus-response translation.

Periosteal Needling to the Cervical Articular Pillars as an Adjunct Intervention for Treatment of Chronic Neck Pain and Headache: A Case Report

(1) Background: Periosteal dry needling (PDN) involves clinicians using a solid filiform needle to stimulate bone for analgesic purposes. This case report presents the use of PDN to the cervical articular pillars (CAPs) in an 85-year-old female with chronic neck pain and headache. (2) Case description: PDN was applied to the right C2–C3 articular pillars, following trigger point dry needling (TrPDN) and manual therapy, in order to provide a direct sensory stimulus to the corresponding sclerotomes. PDN added over two treatments led to improved cervical range of motion and eliminated the patient’s neck pain and headache at 1 week follow-up. (3) Outcomes: At discharge, clinically relevant improvements were demonstrated on the numeric pain rating scale (NPRS), which improved from an 8/10 on intake to a 0/10 at rest and with all movements. In addition, the patient exceeded the risk adjusted predicted four-point score improvement and the minimal clinically important improvement (MCII) value of four points on the Focus on Therapeutic Outcomes (FOTO) Neck Functional Status (Neck FS). At one month post-discharge, the patient remained symptom-free. (4) Discussion: In the context of an evidence-informed approach for neck pain and headache, PDN led to marked improvements in pain and function. Patient outcomes exceeded predictive analytic expectations for functional gains and efficient utilization of visits and time in days. Combined with other interventions, PDN to the CAPs could be a viable technique to treat chronic neck pain with headache.

Perception of opposite-direction motion in random dot kinematograms

ABSTRACT Computational models of motion perception suggest that the perceived direction of weak motion signals may sometimes be directly opposite to the true stimulus motion direction. However, this possibility cannot be assessed by using standard 2AFC motion discrimination paradigms because two opposite directions of motion were used in most studies (e.g., leftward vs. rightward). We were able to obtain robust evidence of opposite-direction motion reports by using a random-dot-kinematogram (RDK) paradigm in which the motion direction varied over 360° and observers were asked to estimate the exact motion direction. These opposite-direction motion reports were replicable across multiple display types and feedback conditions, and observers had greater confidence in their opposite-direction responses than in true guess responses. When we fed RDKs into a computational model of motion processing, we found that the model estimated substantial motion activity in the direction opposite to the coherent stimulus direction, even though no such motion was objectively present in the stimuli, suggesting that the opposite-direction motion perception may be a consequence of the properties of motion-selective neurons in visual cortex. Together, these results demonstrate that the known properties of the visual system may lead to reports of motion that are directly opposite to the true direction.

Effects of Adding Noise to Circuit Model and Numerical Model of Spontaneous Otoacoustic Emissions

Spontaneous otoacoustic emissions have long been modeled using self-excited, nonlinear oscillators. The van der Pol oscillator is a common choice, as many of its properties reflect those of SOAEs: both can begin oscillation in the absence of a direct stimulus, both have narrow frequency bands, and both become stable over time, to name a few. Yet such an idealized equation cannot have a one-to-one correspondence with SOAEs in all factors. Many previously used mathematical and circuit models lack the addition of noise to more accurately show how real world SOAEs operate in an organism’s ear, where noise from the environment is almost entirely unavoidable. The inclusion of uniformly distributed noise in both numerical and circuit models of the van der Pol oscillator was studied to determine whether these models can still accurately explicate SOAEs when modified to be more realistic. In both cases, both models retained the attributes of real world SOAEs despite the addition of noise, allowing them to serve as more useful and accurate models of the phenomenon.

Explicit vs. implicit spatial processing in arrow vs. eye-gaze spatial congruency effects

Arrows and gaze stimuli lead to opposite spatial congruency effects. While standard congruency effects are observed for arrows (faster responses for congruent conditions), responses are faster when eye-gaze stimuli are presented on the opposite side of the gazed-at location (incongruent trials), leading to a reversed congruency effect (RCE). Here, we explored the effects of implicit vs. explicit processing of arrows and eye-gaze direction. Participants were required to identify the direction (explicit task) or the colour (implicit task) of left or right looking/pointing gaze or arrows, presented to either the left or right of the fixation point. When participants responded to the direction of stimuli, standard congruency effects for arrows and RCE for eye-gaze stimuli were observed. However, when participants responded to the colour of stimuli, no congruency effects were observed. These results suggest that it is necessary to explicitly pay attention to the direction of eye-gaze and arrows for the congruency effect to occur. The same pattern of data was observed when participants responded either manually or verbally, demonstrating that manual motor components are not responsible for the results observed. These findings are not consistent with some hypotheses previously proposed to explain the RCE observed with eye-gaze stimuli and, therefore, call for an alternative plausible hypothesis.

Moving bar of light evokes vectorial spatial selectivity in the immobile rat hippocampus.

Visual cortical neurons encode the position and motion direction of specific stimuli retrospectively, without any locomotion or task demand1. The hippocampus, which is a part of the visual system, is hypothesized to require self-motion or a cognitive task to generate allocentric spatial selectivity that is scalar, abstract2,3 and prospective4-7. Here we measured rodent hippocampal selectivity to a moving bar of light in a body-fixed rat to bridge these seeming disparities. About 70% of dorsal CA1 neurons showed stable activity modulation as a function of the angular position of the bar, independent of behaviour and rewards. One-third of tuned cells also encoded the direction of revolution. In other experiments, neurons encoded the distance of the bar, with preference for approaching motion. Collectively, these demonstrate visually evoked vectorial selectivity (VEVS). Unlike place cells, VEVS was retrospective. Changes in the visual stimulus or its predictability did not cause remapping but only caused gradual changes. Most VEVS-tuned neurons behaved like place cells during spatial exploration and the two selectivities were correlated. Thus, VEVS could form the basic building block of hippocampal activity. When combined with self-motion, reward or multisensory stimuli8, it can generate the complexity of prospective representations including allocentric space9, time10,11 and episodes12.

The potential use of virtual reality in vestibular rehabilitation of motion sickness

ObjectiveMotion sickness (MS) can be triggered by direct or indirect stimuli due to mismatches in the visual-vestibular autonomic pathways. Various studies in the literature have shown that virtual reality technologies can generate provocative stimuli for MS. Therefore, our primary aim is to investigate the usability of virtual reality systems in MS rehabilitation Methods20 normal and 19 MS patients were included. A total of six virtual reality rehabilitation sessions (VRrs) with a game called “Roller Coaster Dreams” playable via PlayStation VR Head Mounted Display were applied thrice a week for 2 weeks, or twice a week for 3 weeks. Participants were evaluated at the pre-rehabilitation phase twice and after third and sixth rehabilitation sessions with the sensory organization test (SOT). The effectiveness of the rehabilitation program was statistically analyzed by comparing the results of SOTs. ResultsAll SOT results of the patient group were compared each other to evaluate the effectiveness of rehabilitation. According to the post-hoc comparisons, a statistically significant difference was found between the 1st, 2nd, 3rd, and 4th SOT- Equilibrium Scores; Condition 2 (p = 0.043), Condition 3 (p = 0.006), Condition 4 (p = 0.031), Condition 5 (p = 0.002) and Condition 6 (p = 0.040). There is no difference obtained in Condition 1 (p > 0.05). The Equilibrium Scores of SOT 3rd and SOT 4th were similar and 4th SOT-Equilibrium Scores were the highest among all SOT measurements. The results show that while the first three sessions were accepted as an orientation and adaptation sessions, 4th, 5thand 6th sessions are habilitation sessions. ConclusionsVR proved to be significantly effective and useful for MS rehabilitation. Additionally, observations indicated that using VR makes rehabilitation fun, increases the efficiency of the process, and reduces the risk of inadaptability to exercise.

Gain control by sparse, ultra-slow glycinergic synapses.

In the retina, ON starburst amacrine cells (SACs) play a crucial role in the direction-selective circuit, but the sources of inhibition that shape their response properties remain unclear. Previous studies demonstrate that ∼95% of their inhibitory synapses are GABAergic, yet we find that the light-evoked inhibitory currents measured in SACs are predominantly glycinergic. Glycinergic inhibition is extremely slow, relying on non-canonical glycine receptors containing α4 subunits, and is driven by both the ON and OFF retinal pathways. These attributes enable glycine inputs to summate and effectively control the output gain of SACs, expanding the range over which they compute direction. Serial electron microscopic reconstructions reveal three specific types of ON and OFF narrow-field amacrine cells as the presumptive sources of glycinergic inhibition. Together, these results establish an unexpected role for specific glycinergic amacrine cells in the retinal computation of stimulus direction by SACs.

Compressive forces driven by lateral actin fibers are a key to the nuclear deformation under uniaxial cell-substrate stretching

Cells sense the direction of mechanical stimuli including substrate stretching and show morphological and functional responses. The nuclear deformation with respect to the direction of mechanical stimuli is thought of as a vital factor in mechanosensitive intracellular signaling and gene transcription, but the detailed relationship between the direction of stimuli and nuclear deformation behavior is not fully solved yet. Here, we assessed the role of actin cytoskeletons in nuclear deformation caused by cell substrate stretching with different directions. Cells on a PDMS stretching chamber were subjected to a step-strain and changes of long- and short-axes of nucleus before and after stretching were evaluated in terms of nuclear orientation against the direction of stretching. Nuclei oriented parallel to the stretching direction showed elongation and shrinkage in the long and short axes, respectively, and vice versa. However, calculation of the aspect ratio (ratio of long- and short-axes) changes revealed orientation-depend nuclear deformation: The nucleus oriented parallel to the stretching direction showed a greater aspect ratio change than it aligned in the perpendicular direction of the stretching. A decrease in actin cytoskeletal tension significantly changed the nuclear deformation only in the short axis direction, thereby abolishing the orientation-depend deformation of the nucleus. These results suggest that lateral compressive forces exerted by the actin cytoskeleton is a key factor of orientation-depend deformation in short axis of the nucleus under the cell-substrate stretching condition, and may be crucial for mechano-sensing and responses to the cell-substrate stretching direction.

Dorsal scapholunate interosseous ligament: ultrasound evaluation between dominant and non-dominant wrist in young sports patients.

The dorsal component of the scapholunate ligament, is the strongest component, in fact it has a maximum tensile strength of 300N and mainly controls flexion and extension. In a recent study, the thickness and length of the dorsal component of SLIL was measured using ultrasound image, the length of the dorsal scapholunate ligament was 7.5mm ± 1.4mm and the thickness of 1.8mm ± 0.4mm. We evaluate 60 wrists of 30 young athletic volunteers with ultra-sound image, comparing the thickness variations of the dorsal component of SLIL between the dominant and non-dominant wrist, to confirm our hypothesis that the dorsal component SLIL has proprioceptive activity and therefore the thickness of the ligament increases in following wrist activity. With a high-frequency ultrasound probe > 15MHz (Sonoscape X3 Pro) we evaluated 60 wrists of 30 young men (16 males and 14 females, 20-38years old) manual sports volunteers (10 tennis players, 8 padel players, 7 swimmers, 5 weight lifters) with no recent ligament injuries of the hand or wrist to participate in the study, we compared the dorsal component of SLIL between the dominant and non-dominant wrist. Dorsal SLIL was visualized in all 60 volunteers wrists. We measured an average scapholunate dorsal ligament length 7.7mm and average thickness of 2.3mm in the dominant wrist and average 7.2mm in length and average 1.9mm thickness in the non dominant wrist. The mean dorsal scapholunate interval was average 4.9mm and the mean central interval was average 2.1mm in the dominant wrist and 4.7mm and 1.8mm in the non dominant wrist, so that meas-urements remained unchanged with those reported by previous authors. In our study we ultrasonographically measured an average scapholunate dorsal ligament length 7.7mm and average thickness of 2.3mm in the dominant wrist and average 7.2mm in length and average 1.9mm thickness in the non dominant wrist. This confirms our hypothesis that there is a direct stimulus on the ligamentous component of the dor-sal SLIL in the dominant wrist following repeated uses and activities such as to cause an increase in thickness of the dorsal ligament to highlight the possibility of a proprioceptivity of the ligament if subjected to continuous training. IV.

Recognition of rotated objects and cognitive offloading in dogs

SummaryRecognition of rotated images can challenge visual systems. Humans often diminish the load of cognitive tasks employing bodily actions (cognitive offloading). To investigate these phenomena from a comparative perspective, we trained eight dogs (Canis familiaris) to discriminate between bidimensional shapes. We then tested the dogs with rotated versions of the same shapes, while measuring their accuracy and head tilts. Although generalization to rotated stimuli challenged dogs (overall accuracy: 55%), three dogs performed differently from chance level with rotated stimuli. The amplitude of stimulus rotation did not influence dogs’ performance. Interestingly, dogs tilted their head following the direction and amplitude of rotated stimuli. These small head movements did not influence their performance. Hence, we show that dogs might be capable of recognizing rotated 2D objects, but they do not use a cognitive offloading strategy in this task. This work paves the way to further investigation of cognitive offloading in non-human species.

Perception of Coherent Motion in Infantile Nystagmus Syndrome.

PurposeResearch on infantile nystagmus syndrome (INS) and motion perception is limited. We investigated how individuals with INS perform coherent motion tasks. Particularly, we assessed how the null position affects their performance.MethodsSubjects with INS and controls identified the direction of coherent motion stimuli (22 subjects with INS and 13 controls) in a two-alternative forced-choice design. For subjects with INS, testing was done at the null position and 15 degrees away from it. If there was no null, testing was done at primary gaze position and 15 degrees away from primary. For controls, testing was done at primary gaze position and 20 degrees away from primary. Horizontal and vertical motion coherence thresholds were determined.ResultsSubjects with INS showed significantly higher horizontal and vertical motion coherence thresholds compared with controls at both gaze positions (P < 0.001). Within the INS group, for 12 subjects with INS who had an identified null position, no differences in coherence thresholds were found between their null and 15 degrees away from it (P > 0.05).ConclusionsCoherent motion perception was impaired in subjects with INS. The null position did not significantly influence motion coherence thresholds for either horizontal or vertical motion.

How Does the Central Nervous System Control Forthcoming Movement with Different Emotional Stimuli?

Maintaining postural balance is a key factor in human motor skills, based in part on emotional stimuli. Our objective in this study was to measure the effect of emotion on postural control as influenced by the direction of forthcoming movement. Eighteen right-handed women initiated a step forward or backward or remained in a static position after visualizing an emotional stimulus (positive, negative, or neutral). Center of pressure (COP) parameters (2D velocity, Medio-lateral (ML), and antero-posterior (AP) amplitude) were recorded for 3-second windows for movement direction and emotional stimulus. We observed a motion * direction effect on 2D velocity, characterized by a decrease in the emotional stimulus and static direction windows. The participants' ML amplitude was influenced by direction, and their reduced amplitude was evident in the presence of emotions. AP amplitude was high in the direction versus emotion window. In the static position, the AP amplitude was high in the direction window and low in the emotion window. The participants' movement planning and programming phase (direction window) was characterized by less oscillation for forward or backward movements and more oscillation before movement, suggesting anticipatory postural adjustments in the emotion window. Static direction was characterized by low oscillation, compared to forward and backward movement and in negative versus positive emotional context, proving the interactive impact of direction and emotion on COP amplitudes. Thus, postural control was influenced by both movement (direction) and emotional content (valence). This study provided insight regarding the interactive effect of emotion and direction on planning and programming forthcoming movement.

Selective Interruption of Auditory Interhemispheric Cross Talk Impairs Discrimination Learning of Frequency-Modulated Tone Direction But Not Gap Detection and Discrimination.

Functional hemispheric lateralization is a basic principle of brain organization. In the auditory domain, the right auditory cortex (AC) determines the pitch direction of continuous auditory stimuli whereas the left AC discriminates gaps in these stimuli. The involved functional interactions between the two sides, mediated by commissural connections, are poorly understood. Here, we selectively disrupted the interhemispheric cross talk from the left to the right primary AC and vice versa using chromophore-targeted laser-induced apoptosis of the respective projection neurons, which make up 6-17% of all AC neurons in Layers III, V, and VI. Following photolysis, male gerbils were trained in a first experimental set to discriminate between rising and falling frequency-modulated (FM) tone sweeps. The acquisition of the task was significantly delayed in lesioned animals of either lesion direction. However, the final discrimination performance and hit rate was lowest for animals with left-side lesioned commissural neurons, demonstrating that also information from the left AC is relevant for FM direction learning. Photolysis after successful learning did not affect the retrieval of the learned task, indicating that the disruption during learning was not because of a general functional impairment. In a second experimental set, the gerbil's ability to detect and discriminate small silent gaps of varying length within FM sweeps was tested. This ability was also preserved after interhemispheric disruption. Taken together, interhemispheric communication between the left and right AC is important for the acquisition of FM tone direction learning but not for its retrieval and for gap detection and gap duration discrimination.SIGNIFICANCE STATEMENT Hemispheric lateralization of neuronal functions such as speech and music processing in humans are common throughout the brain; however, the involved interhemispheric interactions are ill-defined. Here, we show that the selective photolytic disruption of auditory cortical commissural connections in rodents impairs the acquisition but not retrieval of a frequency-modulated tone direction discrimination task. The final discrimination performance and hit rate was lowest for animals with lesioned left-to-right-side projections; thus, although right auditory cortex is dominant, left auditory cortex is also relevant for learning this task. The detection and discrimination of small gaps within the tone sweeps remain intact, suggesting a pathway for the processing of these temporal structures, which could be independent from the lesioned interhemispheric cross talk.

What gaze adds to arrows: Changes in attentional response to gaze versus arrows in childhood and adolescence.

From early ages, gaze acts as a cue to infer the interests, behaviours, thoughts and emotions of social partners. Despite sharing attentional properties with other non-social directional stimuli, such as arrows, gaze produces unique effects. A spatial interference task revealed this dissociation. The direction of arrows was identified faster on congruent than on incongruent direction-location trials. Conversely, gaze produced a reversed congruency effect (RCE), with faster identifications on incongruent than congruent trials. To determine the emergence of these gaze-specific attentional mechanisms, 214 Spanish children (4-17years) divided into 6 age groups, performed the aforementioned task across three experiments. Results showed stimulus-specific developmental trajectories. Whereas the standard effect of arrows was unaffected by age, gaze shifted from an arrow-like effect at age 4 to a gaze-specific RCE at age 12. The orienting mechanisms shared by gaze and arrows are already present in 4-year olds and, throughout childhood, gaze becomes a special social cue with additional attentional properties. Besides orienting attention to a direction, as arrows would do, gaze might orient attention towards a specific object that would be attentionally selected. Such additional components may not fully develop until adolescence. Understanding gaze-specific attentional mechanisms may be crucial for children with atypical socio-cognitive development.

Migraine phenotype differentially modulates the attentional network: A cross sectional observation study

Background: Signs of distinct brain dysfunction in patients where migraine intersects with vertigo (i.e. vestibular migraine (VM)), remain elusive. As migraine and vertigo can both independently modulate attentional processes, here we seek the utility of the attentional network to functionally differentiate patients. Methods: We used the Attentional Network Task (ANT) to elucidate three separate functional networks: Alerting, orienting and resolving conflict. 120 participants had to attend to the direction of a target visual stimulus, while other parameters were simultaneously manipulated. Reaction times across the networks were assessed in, (i) 30 healthy controls, (ii) 30 VM patients, (iii) 30 patients with migraine without vertigo, and (iv) 30 patients with benign paroxysmal positional vertigo (BPPV) but no migraine. Results: Patients with VM (mean = 737.1 ms, SEM = 28), migraine (mean = 735.3 ms, SEM = 36.4), and BPPV (mean = 720.3 ms SEM = 24.3) all exhibited significantly delayed ANT reaction times compared to healthy controls (mean = 661.3 ms, SEM = 23.4). Specific attentional network deficits were observed for resolving conflict in VM, alerting in migraine and orienting in BPPV. Conclusion: VM patients displayed deficits in executive function characterized by an inability to focus attentional resources and suppress peripheral distractors, whereas migraineurs without vertigo exhibited changes in the alerting network that reflects hypervigilance.

Towards a green and sustainable recovery from COVID-19

Whilst COVID-19 has left a devastating trail of economic and social losses, it has spurred incidental transitory positive externalities for the environment and climate. Key among these include; improved air and water quality, clearer skies and a projected 8% global blip in carbon emissions by the end of 2020. The global wave of restrictive lock downs implemented to contain the spread of COVID-19 in the short term account for these gains. The lockdowns were defined by limited public and private travel, closure of airports and borders, and a decline in industrial activity. However, most of these climate and environmental gains were secondary effects of the COVID-19 induced lockdowns and not based on decisive deliberate policy action, which casts doubts on their sustainability and ability to contribute to a green economy transition. Sustaining accrued environmental and climate benefits will depend on the direction of the COVID-19 stimuli and recovery packages – whether they are designed to work for the planet or against it. This article therefore elaborates on how state and non-state actors across the globe ought to be agile in building back sustainably to upend the ongoing collision course between the planet and economic development. It emphasizes the use of Sustainable Development Goals and Nationally Determined Contributions on climate change (NDCs) as a compass to shape the direction of COVID-19 recovery packages. It further enumerates six strategies that must underpin recovery packages to ensure win-win for the economy, society, and the planet.

Impact of free Fall Impact versus Treadmill Physical Exercise Programs: Which is Most Osteogenic?

Exercise plays a key role for bone remodeling throughout our lives. Within bone cells, osteocytes have the ability to translate mechanical stimuli to bone anabolic cellular signaling. A variety of protocols have been used to apply both direct and indirect stimuli to bone. Herein, we compared running and free fall impact exercise protocols and their effects on markers of osteogenesis and bone strength.

Современное представление о витамине D и генетической регуляции воспаления на примере бронхиальной астмы

Bronchial asthma (BA) is a heterogeneous chronic inflammatory disease characterized by a variety of symptoms in the form of wheezing, breathlessness, chest tightness and/or cough, as well as variable exhaled airflow limitation, with both the combination of symptoms and airflow limitation changing with time and intensity. Asthma is associated with both airway hyperresponsiveness to direct or indirect stimuli and chronic airway inflammation. Therapy for BA in accordance with national guidelines and clinical recommendations successfully controls asthma symptoms in most patients. However, there are several problems. Firstly, up to 5% of patients with asthma have a refractory course, respond inadequately to traditional therapeutic approaches and, therefore, are at greater risk of life-threatening asthma exacerbations. Secondly, a significant number of patients, even with mild to moderate asthma, have poor symptom control and may experience severe exacerbations. Low vitamin D levels are associated with decreased lung function, increased asthma exacerbations, and drug use, although it is not clear whether there is a causal relationship between these observations, and whether asthma patients may benefit from vitamin D supplementation. The authors present in this literature review the mechanisms by which vitamin D can reduce the severity of inflammation in BA. The research is focused on studying the mechanisms of chronic respiratory inflammation and their exogenous and genetic regulation involving genetic variants of the VDR gene and vitamin D metabolites. Keywords: children, vitamin D, 25(OH)D deficiency, asthma, inflammation, VDR

Cover Feature: Catch and Release Chemotaxis (ChemSystemsChem 2/2022)

The Front Cover shows the repetition of catch and release chemotaxis, which was studied by using a self-propelled 6-methylcoumarin (6-MC) disk floating on water. A tablet of Na3PO4 placed at the bottom of the water phase acted as the chemical stimulus by inducing a variation in surface tension. The self-propelled object, the 6-MC disk, moves in the direction of the chemical stimulus (top left) and it is caught by the stimulus (top right), that is, by the chemical reaction between 6-MC and OH−. When OH− is consumed, the 6-MC disk is released from the tablet and moves towards the higher surface tension (bottom). More information can be found in the Article by Masaharu Nagayama, Satoshi Nakata and co-workers.