Stimulation Of Mechanoreceptors Research Articles

Sonic restoration: acoustic stimulation enhances plant growth-promoting fungi activity.

Ecosystem restoration interventions often utilize visible elements to restore an ecosystem (e.g. replanting native plant communities and reintroducing lost species). However, using acoustic stimulation to help restore ecosystems and promote plant growth has received little attention. Our study aimed to assess the effect of acoustic stimulation on the growth rate and sporulation of the plant growth-promoting fungus Trichoderma harzianum Rifai, 1969. We played a monotone acoustic stimulus (80 dB sound pressure level (SPL) at a peak frequency of 8 kHz and a bandwidth at -10 dB from the peak of 6819 Hz-parameters determined via review and pilot research) over 5 days to T. harzianum to assess whether acoustic stimulation affected the growth rate and sporulation of this fungus (control samples received only ambient sound stimulation less than 30 dB). We show that the acoustic stimulation treatments resulted in increased fungal biomass and enhanced T. harzianum conidia (spore) activity compared to controls. These results indicate that acoustic stimulation influences plant growth-promoting fungal growth and potentially facilitates their functioning (e.g. stimulating sporulation). The mechanism responsible for this phenomenon may be fungal mechanoreceptor stimulation and/or potentially a piezoelectric effect; however, further research is required to confirm this hypothesis. Our novel study highlights the potential of acoustic stimulation to alter important fungal attributes, which could, with further development, be harnessed to aid ecosystem restoration and sustainable agriculture.

Interventions to Reduce Intra-Operative and Post-Operative Pain Associated with Routine Dental Procedures in Children: A Systematic Review and Meta-Analysis.

implementing appropriate pharmacological and non-pharmacological interventions to alleviate pain related to routine dental procedures in paediatric patients could enhance children's ability to manage dental care. The aim of this review was to investigate the effectiveness of and provide recommendations for interventions that can be used to reduce intra-operative and post-operative pain associated with routine paediatric dental procedures. A systematic review of randomised controlled clinical trials (RCT) was conducted. Multiple electronic databases were systematically searched. The Cochrane risk-of-bias tool for RCTs was used to evaluate the quality of the included studies. A meta-analysis was performed to determine the effectiveness of the interventions using the Cohen's d standardised mean differences (SMD) and 95% confidence intervals (CIs) for continuous outcomes. The GRADE tool was used to assess the certainty of evidence to make recommendations. The review included forty-five RCTs comprising 3093 children. Thirty-seven RCTs were included in the meta-analysis, which showed the effectiveness of behavioural interventions (SMD = -0.50, 95% CI -0.83 to -0.18), mechanoreceptor and thermal receptor stimulation (SMD = -1.38, 95% CI -2.02 to -0.73) for intra-operative pain, and pre-emptive oral analgesics (SMD = -0.77, 95% CI -1.21 to -0.33) for reducing post-operative pain in children receiving routine dental care. The GRADE results for these interventions were strong recommendation (IB) for their use, based on moderate evidence and their benefits far outweighing the harm, and they can be delivered readily with minimal training to reduce the pain experience of paediatric patients.

In vivo measurement of strain in the periodontal space of pig (Sus scrofa) incisors using in-fiber Bragg sensors.

The incisor teeth in pigs, Sus scrofa, function in association with a disc-shaped snout to explore the environment for potential food. Understanding how mechanical loading applied to the tooth deforms the periodontal ligament (PDL) is important to determining the role of periodontal mechanoreceptors during food exploration and feeding. The objective of this study was to use fiber Bragg (FBG) sensors to measure strain in vivo within the PDL space of pig incisors. The central mandibular incisors of pigs underwent spring loaded lingual tipping during FBG strain recording within the labial periodontal space. FBG sensors were placed within the periodontal space of the central mandibular incisors of ~2-3-month-old farm pigs. The magnitude and orientation of spring loads are expected to mimic incisor contact with food. During incisor tipping with load calibrated springs, FBG strains in vitro (N = 6) and in vivo (N = 6) recorded at comparable load levels overlapped in range (-10-20 με). Linear regressions between peak FBG strains, that is, the highest recorded strain value, and baseline strains, that is, strain without applied spring load, were significant across all in vivo experiments (peak strain at 200 g vs. baseline, p = .04; peak strain at 2000 g vs. baseline p = .03; peak strain at 2000 g vs. 200 g, p = .004). These linear relationships indicate that on a per experiment basis, the maximum measured strain at different spring loads showed predictable differences. A Friedman test of the absolute value of peak strain confirmed the significant increase in strain between baseline, 200 g, and 2000 g spring activation (p = .02). Mainly compressive strains were recorded in the labial PDL space and increases in spring load applied in vivo generated increases in FBG strain measurements. These results demonstrate the capacity for FBG sensors to be used in vivo to assess transmission of occlusal loads through the periodontium. PDL strain is associated with mechanoreceptor stimulation and is expected to affect the functional morphology of the incisors. The overall low levels of strain observed may correspond with the robust functional morphology of pig incisors and the tendency for pigs to encounter diverse foods and substrates during food exploration.

P175 PARADOXICAL RESPONSE DURING DOBUTAMINE STRESS ECHOCARDIOGRAPHY: A CASE REPORT

Abstract Background Dobutamine Stress Echo (DSE) is a test widely used in the diagnosis of ischemic heart disease. The purpose of the following work is to describe a clinical case with uncommon behaviour. Case Description: 63–year–old female with dyspnoea on mild exertion, and history of NSTEMI–ACS 5 years prior with Coronary Angiography (CA) finding of 3–vessel coronary artery disease, treated with PCI + stent (DES) of right coronary artery (CDX), untreated disease sub–occlusion of the first marginal obtuse (OM1), and chronic occlusion of the anterior interventricular artery (IVA). We decide for DSE. During 20 mcg/kg/min infusion, the patient reported dyspnoea and paradoxical bradycardia (BP) was documented on the ECG, in the absence of ST changes, with the appearance of akinesia of the basal and mid posterolateral segments and worsening of the inferior hypokinesia, present in basal conditions on Echocardiograms (EC). The BP and the alterations of the ventricular motion (VCA) did not respond to the administration of Atropine (1+1 mg) while the administration of 240 mg of Aminophylline (AM) restored the HR and the VCA to baseline values. The CA demonstrated patency of the CDX with the presence of collateral circulation for IVA and occluded OM1. Discussion This case is characterized by the presence of a double paradox: the BP and the Atropine–Resistance (AR). BP during DEB, as demonstrated in previous studies, occurred in 8% of cases, with signs of significant coronary artery disease in 57% of cases. The BP is an expression of ischemia only in just over half of the patients, in the rest of the cases it appeared referable to the Bezold–Jarish reflex, a vagal reflex determined by the stimulation of the intracardiac mechanoreceptors. In our case, the presence of AR seems to exclude the possibility that bradycardia is due to this reflex. The appearance of paradoxical bradycardia during DSE is a rare complication and can lead to premature termination of the test with inconclusive results. In our case, the BP and the AR confirm the positivity of the test also in consideration of the response to the AM antagonist of Adenosine, which accumulates during ischemia. Conclusions This uncommon response to DSE, where AR and AM response in addition to BP could identify patients with severe coronary artery disease in whom the ischemic response is driven by adenosine accumulation, rather than a vagal reflex responding to atropine administration.

Hydrogel Magnetomechanical Actuator Nanoparticles for Wireless Remote Control of Mechanosignaling In Vivo.

As a new enabling nanotechnology tool for wireless, target-specific, and long-distance stimulation of mechanoreceptors in vivo, here we present a hydrogel magnetomechanical actuator (h-MMA) nanoparticle. To allow both deep-tissue penetration of input signals and efficient force generation, h-MMA integrates a two-step transduction mechanism that converts magnetic anisotropic energy to thermal energy within its magnetic core (i.e., Zn0.4Fe2.6O4 nanoparticle cluster) and then to mechanical energy to induce the surrounding polymer (i.e., pNiPMAm) shell contraction, finally delivering forces to activate targeted mechanoreceptors. We show that h-MMAs enable on-demand modulation of Notch signaling in both fluorescence reporter cell lines and a xenograft mouse model, demonstrating its utility as a powerful in vivo perturbation approach for mechanobiology interrogation in a minimally invasive and untethered manner.

THE WEIGHT-REDUCING EFFECT OF ENDOSCOPICALLY–INSERTED INTRAGASTRIC BALLOONS FOR OBESE PATIENTS FAILED WEIGHT CONTROL WITH LIFESTYLE MODIFICATION AND DRUGS

Background 
 The Food and Drug Administration (FDA) recently approved three intragastric balloons (IGB) devices, ReShape, ORBERA™, and Obalon, for treating obesity. Given the high cost, complication risk, and invasiveness of bariatric surgery, IGB treatment may present a safer and lower-cost option for weight reduction. IGBs are generally placed in the stomach endoscopically for up to 6 months to reduce gastric capacity, enhance feelings of fullness, and induce weight loss. The mechanism of action likely involves stimulation of gastric mechanoreceptors triggering short-acting vagal signals to brain regions implicated in satiety. Balloon efficacy may be influenced by balloon volume, patient gastric capacity, and treatment duration.
 Objectives 
 To evaluate the efficacy, tolerability, and safety of intra-gastric balloons on weight reduction versus obese patients’ failed weight controlled by dietary changes and drugs.
 Methods
 A retrospective study was performed in Sulaimani City from 2017 to Feb./2018. We included 40 obese patients by the World Health Organization (WHO) definition of BMI≥30. The subjects aged 18-68 years with intra-gastric balloons were inserted by endoscopy for 4-9 months. Anthropometric measurements were obtained before, during and after the removal of intra-gastric balloons.
 Results
 In total, 40 cases of obese patients, 21 (52.5%) females and 19 (47.5%) males. The mean age was 37.1±11.70years with a range of 18-68 years. BMI and weight significantly reduced early 3-month mean weight 12.78±2.81 Kg, and late 6-month mean weight 9.05±1.89 Kg and around 21 Kgs at removal. Only one patient was the IGB removed early by four months and was not included. Late one year after IGB removal, the long-term effect on BMI and weight were recorded and maintained in most persons. 
 Conclusion
 Intragastric balloon (IGB) was effective in our study. The observed weight reduction was maintained through 1 year after removal & IGB appeared safe and tolerable & satisfactory for most obese subjects.

Biocompatible Soft Conductor for Electric-tactile Haptic Interface

Purpose of the study: Haptic technology, which can qualitatively expand virtual or augmented reality experiences beyond the sensation of the ear and eye, is realized by electrical and mechanical stimulation of afferent nerves or mechanoreceptors. In this review, researchers highlight the biological basis for sensation and suggest the advanced direction in the electric tactile-based haptic system using low impedance materials.
 Methodology: Conductive polymer called “Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)” was examined for chemical properties and biocompatibility. 
 Main Findings: Study of PEDOT:PSS shows the superior property in terms of deformability and electrical performance for developing the low-impedance, skin-like haptic interfaces.
 Implications: To provide wear- comfort, skin-like technologies that impose a negligible physical burden on the user should be used. The mainstream of haptic technology involves the development of a system that could provide myriads of sensations to the skin through not only to the fingertips but also to some or all regions of the body.
 Novelty: Researchers also provide the strategy to impart skin-like property as well as low impedance using hydrogel polymer which is desirable in wearable haptic systems.

IDF21-0164 Effect of stimulating footwear on gait and posture in people with Diabetes and foot complications

Background: The maintenance of human posture and gait requires the central integration of afferent information and is highly dependent on the somatosensory information from the plantar cutaneous mechanoreceptors. Normal foot structure sends undistorted signals to the brain due to the proper stimulation of mechanoreceptors in the foot soles and therefore brain responds properly by adjusting the skeletal framework into good posture. In the case of abnormal foot structure, the brain receives distorted signals due to poor stimulation of mechanoreceptors. As a result, the brain generates alternate signals to deal with these abnormalities, resulting in poor gait and posture. Aim: The main intention of this study was to develop a new footwear with ultrasonic sensors that emit ultrasonic waves at a lower frequency of 35 kHz to properly stimulate plantar mechanoreceptors. The objective of this study was to evaluate the effect of the above footwear on gait and posture of people with diabetic neuropathy, with foot deformity (bow knee, bilateral genu valgum, leg length discrepancy, abnormal foot arch) and also with foot and/or joint discomfort after 15days of wearing it for 10minutes each day. Method: A total of 5 (3 men and 2 women) subjects volunteered for this study. Informed consent was obtained from each participant. Subjects were prepared using a specialized wireless inertial sensor as per the protocol and were asked to walk freely on the sensorized platform for measuring their plantar pressure and also their spatial temporal parameters. Data was captured using Plantar pressure measuring device and wearable inertial system (BTSBioengineering, Italy). For data analysis, three trials were recorded. A single best trial was selected for processing and reporting. After completion of the initial assessment, subjects were asked to wear the test footwear as a therapy for 10 minutes every day for 15 days. When the switch is on the sensors will emit ultrasound at a frequency of 35 kHz. Following the completion of the 15-days, the subjects were re-evaluated using plantar pressure measuring device and wearable inertial system. Then a comparison was made between the data collected before and after therapy. Results: See Table 1 and Table 2.Table 1Results of Spatial temporal data before and after the therapy. Open table in a new tab Table 2Results of Plantar pressure data before and after the therapy. Open table in a new tab Discussion: The spatiotemporal data, in Table 1, shows a considerable improvement after using the developed footwear. There was a considerable decrease in double limb support time and increase in single limb support, indicating that the subject was able to minimize the contact time of the foot during walking which significantly minimizes foot plantar pressure loading which is the precursor of diabetic foot ulcer. Also, there was a significant increase in cadence and gait velocity after completion of therapy. The plantar pressure data, in Table 2, indicates an increase in the foot contact area which significantly improve the foot pressure distribution, leads to reduction in peak plantar pressure. Also, there was a shift in the maximum pressure from lateral foot to medial foot which shows the distribution of body weight shifted from lateral to medial which is the sign for good posture.

About the Cover

Next article FreeAbout the CoverPDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinked InRedditEmailQR Code SectionsMoreThis issue’s cover shows clonal sea anemones Diadumene (Haliplanella) lineata. Sea anemones are sessile marine cnidarians. Cnidarians use organelles called nematocysts made and deployed by cnidocytes to capture and kill prey rapidly following sensory stimulation. When triggered, nematocysts deploy an eversible barbed tubule through which a venom is injected into prey. Backward-facing barbs and an anchoring mechanism on the tentacle combine to retain captured prey, while tentacles bearing prey bend toward the mouth for ingestion.Nematocyst discharge is under hierarchal control of two classes of chemoreceptors: vibration-sensitive mechanoreceptors (VSMs) and contact-sensitive mechanoreceptors (CSMs). Chemoreceptors and VSMs on two or more supporting cells adjacent to cnidocytes form cnidocyte-supporting cell complexes (CSCCs), the functional units of nematocyst discharge. Three types of CSCCs regulate nematocyst discharge in D. lineata: (i) Type As have associated NANA chemoreceptors that tune vibration-sensitive mechanoreceptors (VSMs) to the movements of swimming prey that, in turn, predispose CSMs to trigger; (ii) Type Bs are sensitized by N-acetylneuraminic acid (NANA) that predisposes triggering CSMs to physical contact; and (iii) Type C CSCCs are activated by physical stimulation of contact-sensitive mechanoreceptors. The CSMs and VSMs require extracellular calcium, and the delay from triggering to discharge is measured in milliseconds. Such features suggest mechanogated ion channels, features shared by several types of transient receptor potential (TRP) channels.On pages 48–61 of this issue, A. Nam, S. Quarshie, M. Kimble, and D. A. Hessinger test general and selective TRP channel blockers, using a quantitative prey killing assay to implicate a variety of TRP channels involved in nematocyst-mediated prey killing. They found that non-selective TRP blockers, such as gadolinium (Gd+3) and lanthanum (La+3), potently and broadly inhibit both nematocyst discharge and prey killing from Type Bs and Cs, which is consistent with TRP channel involvement. They then demonstrated that three selective TRPV4 blockers inhibited prey killing from vibration-sensitive Type A CSCCs. Their data implicate TRPV4-like channels in nematocyst discharge from vibration-sensitive Type As and pharmacologically distinct TRP channels in Type Bs and Cs.Credits: Photo of Diadumene lineata by David Reed, with permission. Available under Creative Commons License CC BY-NC-SA 2.0. Cover design: Olivia Kinker, University of Chicago Press. Next article DetailsFiguresReferencesCited by The Biological Bulletin Volume 242, Number 1February 2022 Published in association with the Marine Biological Laboratory Article DOIhttps://doi.org/10.1086/719750 Views: 936Total views on this site © 2022 The University of Chicago. All rights reserved.PDF download Crossref reports no articles citing this article.

Functional Characterization of TRPV-Like Ion Channels Involved in Nematocyst Discharge from the Sea Anemone Diadumene lineata.

AbstractCnidarians require mechanical stimuli to trigger nematocyst discharge and initiate feeding behaviors. The interval from triggering stimulus to response is tens of microseconds, making it likely that mechanically gated ion channels trigger nematocyst discharge. Because many transient receptor potential channels are mechanically gated, we hypothesized that nematocyst discharge involves transient receptor potential channels. We therefore tested various transient receptor potential channel inhibitors to determine whether they inhibit nematocyst discharge and prey killing in the acontiate sea anemone (Actinaria) Diadumene lineata (a.k.a. Haliplanella luciae). Three types of cnidocyte supporting cell complexes regulate nematocyst discharge in anemones: Types C, B, and A. Discharge from Type Cs is directly triggered by stimulation of contact-sensitive mechanoreceptors, while Type Bs require activation of chemoreceptors from prey-derived N-acetylated sugars to sensitize contact-sensitive mechanoreceptors. In Type As, activated chemoreceptors tune vibration-sensitive mechanoreceptors that predispose contact-sensitive mechanoreceptors for triggering. The non-selective transient receptor potential channel blockers lanthanum and gadolinium dose-dependently inhibited about 80% of prey killing and all nematocyst discharge from Type Bs and Type Cs, but not Type As. The selective transient receptor potential vanilloid 4 (TRPV4) blocker GSK2193874 inhibited Type As and Type Bs. However, the selective TRPV4 blockers HC-067047 and RN-1734 inhibited only Type As. Thus, three TRPV4-selective blockers implicate TRPV-like involvement in discharge from Type As, whereas GSK2193874 also affected Type Bs. Our results suggest that a TRPV-like homolog plays an essential role in nematocyst-mediated prey killing from Type As, whereas other transient receptor potential channels are likely involved in discharge from Type B and C cnidocyte supporting cell complexes.

Coupled experimental and computational approach to stomach biomechanics: Towards a validated characterization of gastric tissues mechanical properties

Gastric diseases are one of the most relevant healthcare problems worldwide. Interventions and therapies definition/design mainly derive from biomedical and clinical expertise. Computational biomechanics, with particular regard to the finite element method, provides hard-to-measure quantities during in-vivo tests, such as strain and stress distribution, leading to a more comprehensive and promising approach to improve the effectiveness of many different clinical activities. However, reliable finite element models of biological organs require appropriate constitutive formulations of building tissues, whose parameters identification needs an experimental campaign consisting in different tests on human tissues and organs. The aim of the reported here research activities was the identification of mechanical properties of human gastric tissues. Human gastric specimens were tested at tissue, sub-structural and structural levels, by tensile, membrane indentation and inflation tests, respectively. On the other hand, animal experimentations on tissue layers from literature pointed out the mechanical response at sub-tissue level during tensile loading conditions. In detail, the analysis of experimental results at sub-tissue and tissue levels led to a fibre-reinforced visco-hyperelastic constitutive formulation and to the identification of gastric layers mechanical behaviour. Results from experimentations on human samples were coupled with data derived from animal models. Data from sub-structural and structural experimentations were exploited to upgrade and validate the constitutive formulations and parameters. The developed investigations led to a reliable constitutive framework of human gastric tissues that both describe stomach mechanical functionality and allow computational investigations. Indeed, the comparisons among average computational data and experimental medians provided the following RMSEs (Root Mean Square Errors): 0.89 N, 0.15 N for corpus and fundus during membrane indentation test, respectively, and 0.44 kPa during inflation test. Accounting for the magnitude of experimental and computational data, the RMSEs can be considered low and acceptable because they concerned biological samples. In fact, biological tissues and structures are affected by a high inherent inter-samples’ variability, which is detectable in both the geometrical configuration and the mechanical behaviour. The specific values of the here reported RMSEs ensured the reliability of the achieved parameters and the quality of the overall developed procedure.Reliable computational models of the gastric district could become efficient clinical tools to find out the main crucial aspects of bariatric procedures, such as the mechanical stimulation of gastric mechano-receptors. Moreover, the methods of computational biomechanics will permit to run the preliminary tests of new and innovative bariatric procedures, on one hand, predicting the successful rate and the effectiveness, and, on other hand, reducing the use of animal testing.

Continuous gastric saline perfusion elicits cardiovascular responses in freshwater rainbow trout (Oncorhynchus mykiss)

When in seawater, rainbow trout (Oncorhynchus mykiss) drink to avoid dehydration and display stroke volume (SV) mediated elevations in cardiac output (CO) and an increased proportion of CO is diverted to the gastrointestinal tract as compared to when in freshwater. These cardiovascular alterations are associated with distinct reductions in systemic and gastrointestinal vascular resistance (RSys and RGI, respectively). Although increased gastrointestinal blood flow (GBF) is likely essential for osmoregulation in seawater, the sensory functions and mechanisms driving the vascular resistance changes and other associated cardiovascular changes in euryhaline fishes remain poorly understood. Here, we examined whether internal gastrointestinal mechanisms responsive to osmotic changes mediate the cardiovascular changes typically observed in seawater, by comparing the cardiovascular responses of freshwater-acclimated rainbow trout receiving continuous (for 4 days) gastric perfusion with half-strength seawater (½ SW, ~ 17 ppt) to control fish (i.e., no perfusion). We show that perfusion with ½ SW causes significantly larger increases in CO, SV and GBF, as well as reductions in RSys and RGI, compared with the control, whilst there were no significant differences in blood composition between treatments. Taken together, our data suggest that increased gastrointestinal luminal osmolality is sensed directly in the gut, and at least partly, mediates cardiovascular responses previously observed in SW acclimated rainbow trout. Even though a potential role of mechano-receptor stimulation from gastrointestinal volume loading in eliciting these cardiovascular responses cannot be excluded, our study indicates the presence of internal gastrointestinal milieu-sensing mechanisms that affect cardiovascular responses when environmental salinity changes.

No change in foot soft tissue morphology and skin sensitivity after three months of using foot orthoses that alter plantar pressure

Altering plantar load using foot orthoses (FOs) may alter the mechanical work required of internal structures and change the size of muscle and connective tissues. Skin sensitivity might also change as a result of altering mechanoreceptor stimulation. This study investigated the effects of FOs on foot soft tissue morphology and skin sensitivity over three months of use. Forty-one healthy participants wore prefabricated FOs (n = 23) or no insert (n = 18) for three months. The FOs were prescribed specific to each participant, using criteria of a change in peak pressure of 8% in the medial arch (pressure increase) and medial heel (pressure decrease). Ultrasound images were recorded pre- and post-FOs use to derive cross-sectional area and thickness of: abductor hallucis, flexor hallucis brevis, flexor digitorum brevis and the Achilles tendon at the insertion and mid-portion. Plantar fascia thickness was measured at the insertion and midfoot. The minimal detectable difference was established in piloting (n = 7). Skin sensitivity was measured with monofilaments at the dorsum (between the hallux and second toe), medial and lateral heel, medial and lateral arch and the 1st metatarsal head. The FOs increased peak pressure by 15% in the medial arch and reduced it by 21% in the medial heel. None of the changes in soft tissue measurements was greater than the minimal detectable difference and there were no effects of group and time. Skin sensitivity decreased over time at the 1st metatarsal head for both groups, but there was no group effect. Using FOs over three months did not change the foot tissues nor skin sensitivity. This study challenges the notion that FOs make muscles smaller.

A touch of hierarchy: population receptive fields reveal fingertip integration in Brodmann areas in human primary somatosensory cortex

Several neuroimaging studies have shown the somatotopy of body part representations in primary somatosensory cortex (S1), but the functional hierarchy of distinct subregions in human S1 has not been adequately addressed. The current study investigates the functional hierarchy of cyto-architectonically distinct regions, Brodmann areas BA3, BA1, and BA2, in human S1. During functional MRI experiments, we presented participants with vibrotactile stimulation of the fingertips at three different vibration frequencies. Using population Receptive Field (pRF) modeling of the fMRI BOLD activity, we identified the hand region in S1 and the somatotopy of the fingertips. For each voxel, the pRF center indicates the finger that most effectively drives the BOLD signal, and the pRF size measures the spatial somatic pooling of fingertips. We find a systematic relationship of pRF sizes from lower-order areas to higher-order areas. Specifically, we found that pRF sizes are smallest in BA3, increase slightly towards BA1, and are largest in BA2, paralleling the increase in visual receptive field size as one ascends the visual hierarchy. Additionally, we find that the time-to-peak of the hemodynamic response in BA3 is roughly 0.5 s earlier compared to BA1 and BA2, further supporting the notion of a functional hierarchy of subregions in S1. These results were obtained during stimulation of different mechanoreceptors, suggesting that different afferent fibers leading up to S1 feed into the same cortical hierarchy.

Plantar mechanical stimulation attenuates protein synthesis decline in disused skeletal muscle via modulation of nitric oxide level

Both research conducted under microgravity conditions and ground-based space analog studies have shown that air pump-based plantar mechanical stimulation (PMS) of cutaneous mechanoreceptors of the sole of the foot is able to increase neuromuscular activity in the musculature of the lower limbs. This type of stimulation is able to attenuate unloading-induced skeletal muscle atrophy and impaired muscle function. The aim of the present study was to evaluate the effects of PMS on anabolic signaling pathways in rat soleus muscle following 7-day hindlimb suspension (HS) and to elucidate if the effects of PMS on anabolic processes would be NO-dependent. The soles of the feet were stimulated with a frequency of 1-s inflation/1-s deflation with a total of 20 min followed by 10 min rest. This cycle was repeated for 4 h each day. We observed a decrease in the soleus muscle mass after 7-day HS, which was not prevented by PMS. We also observed a decrease in slow-type fiber cross-sectional area (CSA) by 56%, which significantly exceeded a decrease (–22%) in fast-type fiber CSA. PMS prevented a reduction in slow-twitch fiber CSA, but had no effect on fast-twitch fiber CSA. PMS prevented a 63% decrease in protein synthesis after 7-day HS as well as changes in several key anabolic signaling regulators, such as p70S6k, 4E-BP1, GSK3β, eEF-2, p90RSK. PMS also prevented a decrease in the markers of translational capacity (18S and 28S rRNA, c-myc, 45S pre-rRNA). Some effects of PMS on anabolic signaling were altered due to NO-synthase inhibitor (L-NAME) administration. Thus, PMS is able to partially prevent atrophic processes in rat soleus muscle during 7-day HS, affecting slow-type muscle fibers. This effect is mediated by alterations in anabolic signaling pathways and may depend on NO-synthase activity.

NK1 antagonists attenuate tau phosphorylation after blast and repeated concussive injury

Exposure to repeated concussive traumatic brain injury (TBI) and to blast-induced TBI has been associated with the potential development of the neurodegenerative condition known as chronic traumatic encephalopathy (CTE). CTE is characterized by the accumulation of hyperphosphorylated tau protein, with the resultant tau tangles thought to initiate the cognitive and behavioral manifestations that appear as the condition progresses. However, the mechanisms linking concussive and blast TBI with tau hyperphosphorylation are unknown. Here we show that single moderate TBI, repeated concussive TBI and blast-induced mild TBI all result in hyperphosphorylation of tau via a substance P mediated mechanism. Post-injury administration of a substance P, NK1 receptor antagonist attenuated the injury-induced phosphorylation of tau by modulating the activity of several key kinases including Akt, ERK1/2 and JNK, and was associated with improvement in neurological outcome. We also demonstrate that inhibition of the TRPV1 mechanoreceptor, which is linked to substance P release, attenuated injury-associated tau hyperphosphorylation, but only when it was administered prior to injury. Our results demonstrate that TBI-mediated stimulation of brain mechanoreceptors is associated with substance P release and consequent tau hyperphosphorylation, with administration of an NK1 receptor antagonist attenuating tau phosphorylation and associated neurological deficits. NK1 antagonists may thus represent a pharmacological approach to attenuate the potential development of CTE following concussive and blast TBI.

Effect of stimulation of sole mechanoreceptors on voluntary posture control ability

Effect of stimulation of sole mechanoreceptors on voluntary posture control ability

Biomechanical analysis of single-leg stance using a textured balance board compared to a smooth balance board and the floor: A cross-sectional study

BackgroundPrevious research showed that standing on textured surfaces can improve postural control by adapting somatosensory inputs from the plantar foot. The additional stimulation of plantar cutaneous mechanoreceptors by a textured surface during single-leg stance on a balance board may increase afferent information to the central nervous system to accelerate muscular responses and to enhance their accuracy. The additional impact of textured surface during single-leg stance on a balance board on postural control and muscle activity is unknown. Research questionTo investigate the differences of a) postural control during single-leg stance on a textured balance board compared to a smooth balance board and b) activity of lower extremity muscles during single-leg stance on a textured balance board compared to a smooth balance board and the floor. MethodsTwenty-six healthy adults (12 females, 14 males; mean age = 25.4 years) were asked to balance on their randomly assigned left or right leg on a force plate (floor; stable condition), a textured balance board and a smooth balance board (unstable conditions). Center of pressure (CoP) displacements (force plate, Bertec, 1000 Hz) and electromyographic activity (EMG) of eight leg muscles were measured and compared between conditions, respectively. ResultsNeither CoP-displacements, nor EMG activities differed significantly between the textured and the smooth balance board (p > 0.05). Significantly higher muscle activities (p < 0.05) were observed using the balance boards compared to the floor. SignificanceSingle-leg stance using a textured balance board seems not to lead to reduced CoP-displacements compared to a smooth balance board. Muscle activation is significantly increased in both balance board conditions compared to the floor, however, it is not different when both balance board surfaces are compared. It could not be recommended to use a textured balance board for altering muscle activity and improving postural control during single-leg stance in favor of a smooth textured balance board.

Gallbladder distension as a triggering link of the reflex influences of afferent pathological impulses

Objective — to investigate correlation between sonographic gallbladder (GB) parameters and clinical characteristics, results of laboratory investigations and structural and functional cardiac parameters in patients with the ischemic heart disease and arterial hypertension.Materials and methods. The GB sizes were estimated in 64 patients with ischemic heart disease (stable and unstable angina pectoris), in 31 patients with arterial hypertension, overweight or obesity, and 18 healthy persons without cardiovascular disorders. A number of cell ratios and integral hematological indices were calculated, in particular index of immunoreactivity, index of inflammation activity, integral index of inflammation, leukocyte index of intoxication, lymphocyte‑granulocyte index, index of leukocyte shift.Results. It has been established that the increase of GB sizes was associated with activation of inflammation and endogenous intoxication syndromes, inhibition of the immune response and cardiovascular risk factors: elongation of heart electric systole, arterial hypertension, increase of body weight. Distension of GB against the background of cardiovascular pathology was accompanied by the decrease of its contractility (according to ejection fraction). The increase of GB sizes together with the stimulation of GB wall mechanoreceptors may act as a trigger of pathological reflex influence, which leads to the viscero‑visceral cardioneuropathy.Conclusions. The obtained data enabled to open a new direction in the strategy of cardiovascular prophylaxis, the reduction of pathological impulses from a distended gallbladder in cardiovascular patients who was undergone timely lithotripsy and low‑invasive cholecystectomy, are the ways to lower the cardiovascular risk, and the improvement of the state of biliary ducts is an important component of the primary cardiovascular prophylaxis.

Pathophysiological mechanisms of neurological disorders in experimental animals exposed to vibration

The review presents an analysis of literature on the study of nervous system changes in experimental animals exposed to vibration. The hypoxic type of cellular metabolism against the background of vibration is the result of vascular mechanoreceptors stimulation and spasm of blood vessels as well as intravascular pressure phase fluctuations and impaired blood and lymph outflow. Hemodynamic disorders and microangiopathy in the central nervous system can reach the level of cerebral vascular impairment and capillary-trophic insufficiency of the brain. Changes in calcium homeostasis at the cellular and tissue levels is a key mechanism of neuronal destruction occurring alongside with impaired blood supply to the nervous tissue in patients with vibrational disease. Long-term exposure to vibration results in reduced tissue respiration in the brain structures of experimental animals, that is most pronounced in the cortex and leads to a pathological change of spontaneous electrical activity of brain structures. Acute vibration stress stimulated the synthesis and excretion of serotonin not only in the hippocampus and hypothalamus but also in the cerebellum, which explains the disturbances of the oculomotor reactions observed in vibration exposure in the control system of the vertical vestibular ocular reflex. A decrease in the total number of neurons as well as an increase in the number of astroglia cells against the background of paravascular tissue edema were revealed against the background of changes in neurotransmitters levels. An increase in the concentration of the biomarker of structural and functional damage to brain tissue specific protein S-100B accompanies the development of professional sensorineural hearing loss and dysfunction of cerebral level vegetative regulation.