Tactile Function Research Articles

Relations between tactile sensitivity of the finger, arm, and cheek skin over the lifespan showing decline only on the finger.

Touch sensitivity generally declines with age, contributing to loss of manual dexterity and tactile function. We investigated how touch changes over the lifespan, using different tests and on three body sites. We used a classical test of force detection sensitivity, where calibrated monofilaments were applied passively to the right index finger pad, forearm, and cheek. In addition, at the index, we used an active touch spatial discrimination task, developed by our group. Spatial discrimination was estimated through participants' ability to evaluate the distance between parallel bands printed on acrylic plates. Data were collected from 96 healthy women, aged 20-75 years. Force detection and tactile spatial discrimination on the index deteriorated significantly with age; however, no change was found for tactile detection on the forearm or cheek. Tactile detection on the cheek remained remarkably highly sensitive throughout life. There was a significant positive relationship between force detection and spatial discrimination on the index. Further, force detection on the forearm was significantly associated with detection on the index and cheek. Our results suggest a decrease in touch perception with age on the index finger pad, yet a preservation of tactile sensitivity in hairy skin. This opens discussion about the impact of daily activities upon the glabrous hand skin and on the function of hairs in tactile sensitivity. We highlight the need for new methods in evaluating tactile sensitivity on hairy skin.

Association Between Multisensory Impairment and Depression Among Older Adults: A Population-Based Analysis.

In this study, we examine how impairments in vision, hearing, touch, and olfaction relate to depression in older adults, considering both individual and multisensory impairments (MSIs). Analysis of cross-sectional data from a longitudinal investigation involving black and white older adults aged 70 to 79 at enrollment. We studied 1640 black and white participants in the Health ABC study using complete sensory evaluation data from years 3 to 5. Our MSI assessment utilized data obtained for visual acuity, hearing perception, olfactory performance, and tactile function. We performed multivariable logistic regression analyses to examine the associations between the presence of individual and MSIs and depression which was defined as the presence of antidepressants prescribed for depression, or a Center for Epidemiological Studies Depression Scale score of greater than 10. We observed a possible dose-response relationship between the number of sensory impairments and depression. In adjusted models, when compared to no impairments, vision (odds ratio [OR] = 1.45, 95% confidence interval [CI]: 1.09-1.93) and hearing impairments (OR = 1.49, 95% CI: 1.11-1.99) were significantly associated with depression, whereas olfaction (OR = 1.11, 95% CI: 0.83-1.47) and tactile impairments (OR = 1.28, 95% CI: 0.96-1.70) were not. Participants with 3 sensory impairments had a higher rate of depression (OR = 2.05, 95% CI: 1.22-3.54) compared to those without impairments, and this risk increased further for those with 4 sensory impairments (OR = 2.95, 95% CI: 1.48-5.88). The findings suggest that individuals with MSI represent a high-risk population for depression, warranting close monitoring to screen for depression. The study emphasizes the importance of considering multiple sensory impairments in the context of mental health and supports the early identification and monitoring of depression in this population.

Soft Tactile Sensing for Object Classification and Fine Grasping Adjustment Using a Pneumatic Hand With an Inflatable Palm

Power grasps and fine manipulations with a robotic hand usually require dexterity in the fingers and a rich tactile function. In this paper, we propose a novel soft hand with a tactile sensing function and investigate how tactile information can be used to perform object classification and fine grasping adjustments. We first developed a pneumatically driven soft hand with an inflatable palm and bendable fingers, where a TacTip -type sensor and several flex sensors were integrated. The inflatable palm can not only significantly improve grasping but also object sensing. Based on the perspective projection model of a camera, a 3D reconstruction algorithm for the deformed surface of a soft palm is presented. A spatial characterization of geometric information regarding objects based on sensing information from the palm and fingers was deduced and analyzed. A classifier was designed for object classification. Finally, a control method for the fine adjustment of grasps based on tactile sensing information was presented and verified using a series of grasps of different objects with a soft hand. The object classification and contact state sensed by the soft tactile sensors can be used for grasp planning and manipulation control with the soft hand.

Are tactile function and body awareness of the foot related to motor outcomes in children with upper motor neuron lesions?

Somatosensory function can be reduced in children with Upper Motor Neuron (UMN) lesions. Therefore, we investigated relationships between somatosensory functions of the foot and motor outcomes in children with UMN lesions. In this cross-sectional study, we assessed the Tactile Threshold (TT) with monofilaments and body awareness with Tactile Localisation Tasks for spatial-related action (TLTaction) and structural-related perception (TLTperception) body representation at the foot sole. Furthermore, we assessed four motor outcomes: the Selective Control Assessment of the Lower Extremity (SCALE), the modified Timed Up and Go test (mTUG), the Gillette Functional Assessment Questionnaire (FAQ), and the Functional Mobility Scale (FMS). Spearman's correlations (ρ) were applied to assess relationships between the somatosensory function of the foot sole and the applied motor outcomes. Thirty-five children with UMN lesions, on average 11.7 ± 3.4 years old, participated. TLTperception correlated significantly with all lower limb motor outcomes (|ρ|=0.36-0.57; p < 0.05), but TLTaction (|ρ|=0.00-0.27; p = 0.15-0.97, and TT did not (|ρ|=0.01-0.83; p = 0.73-0.94). TLTperception correlated strongly with the Gross Motor Function Classification System (|ρ|=0.62; p = 0.001) in children with cerebral palsy (n = 24). Assessing structural body representation of the foot sole should be considered when addressing lower limb motor impairments, including gait, in children with upper motor neuron lesions. Our results suggest that the assessment of tactile function and spatial body representation may be less related to lower limb motor function.

Bionic artificial skin with a fully implantable wireless tactile sensory system for wound healing and restoring skin tactile function

Tactile function is essential for human life as it enables us to recognize texture and respond to external stimuli, including potential threats with sharp objects that may result in punctures or lacerations. Severe skin damage caused by severe burns, skin cancer, chemical accidents, and industrial accidents damage the structure of the skin tissue as well as the nerve system, resulting in permanent tactile sensory dysfunction, which significantly impacts an individual’s daily life. Here, we introduce a fully-implantable wireless powered tactile sensory system embedded artificial skin (WTSA), with stable operation, to restore permanently damaged tactile function and promote wound healing for regenerating severely damaged skin. The fabricated WTSA facilitates (i) replacement of severely damaged tactile sensory with broad biocompatibility, (ii) promoting of skin wound healing and regeneration through collagen and fibrin-based artificial skin (CFAS), and (iii) minimization of foreign body reaction via hydrogel coating on neural interface electrodes. Furthermore, the WTSA shows a stable operation as a sensory system as evidenced by the quantitative analysis of leg movement angle and electromyogram (EMG) signals in response to varying intensities of applied pressures.

Effect of Normal Force Intensity on Tactile Motion Speed Perception Based on Spatiotemporal Cue.

While the relative motion between the skin and objects in contact with it is essential to everyday tactile experiences, our understanding of how tactile motion is perceived via human tactile function is limited. Previous studies have explored the effect of normal force on speed perception under conditions where multiple motion cues on the skin (spatiotemporal cue, tangential skin deformation cue, and slip-induced vibration cue) were integrated. However, the effect of the normal force on speed perception in terms of each motion cue remains unclear since the multiple motion cues have not been adequately separated in the previously reported experiments. In this study, we aim to elucidate the effect of normal force in situations where the speed perception of tactile motion is based solely on a spatiotemporal cue. We developed a pin-array display which allowed us to vary the intensity of the normal force without causing tangential forces or slip-induced vibrations. Using the display, we conducted two psychophysical experiments. In Experiment 1, we found that the speed of the object was perceived to be 1.12-1.14 times faster when the intensity of the normal force was doubled. In Experiment 2, we did not observe significant differences in the discriminability of tactile speed caused by differences in normal force intensity. Our experimental results are of scientific significance and offer insights for engineering applications when using haptic displays that can only provide spatiotemporal cues represented by normal forces.

Structural Electronic Skin for Conformal Tactile Sensing.

The conformal integration of the electronic skin on the non-developable surface is in great demand for the comprehensive tactile sensing of robotics and prosthetics. However, the current techniques still encounter obstacles in achieving conformal integration of film-like electronic skin on non-developable surfaces with substantial curvatures for contact pressure detection and tactile mapping. In this paper, by utilizing the 3D printing technology to prepare the 3D electrode array in the structural component following its surface curvature, and covering it with a molded functional shell to form the pressure sensitive iontronic interface, a device is proposed to achieve high-sensitive pressure detection and high-fidelity tactile mapping on a complicated non-developable surface, called structural electronic skin (SES). The SES is prepared in a 3D printed fingertip with 46 tactile sensing units distributed on its curved surface, achieving the integration of both structural and tactile functions in a single component. By integrating the smart fingertip into a dexterous hand, a series of demonstrations are presented to show the dead-zone free pressure detection and tactile mapping with high sensitivity, for instance, 2D pulse wave monitoring and robotic injection in a medical robot, object recognition and compliant control in a smart prosthesis.

Architecture of vibrissae in eight rodent species of Ctenohystrica (Rodentia): A comparative SEM study

Our study was conducted within the framework of comparative functional morphology of mammalian skin (Sokolov 1982) and “Trichomorphology” (Hausmann 1930; 1944; Teerink 1991) focusing in particular on specialized tactile organs such as whiskers (vibrissae). The architecture of vibrissae was studied for the first time using SEM in the relict rodent Laonastes aenigmamus and in some other representatives of the clade Ctenohystrica (Rodentia): Ctenodactylus gundi, Pectinator spekei, Proechimys guyannensis, Echimys sp., Trichomys apereoides, Chinchilla lanigera, and Octodon degus with the aim to identify the specific characters for each species. The vibrissal architecture is specific and polymorphic: the rod shape and structure of the medulla show differences between species of different genera and differ from those of guard hairs and spines of the same species. In L. aenigmamus, the vibrissal medulla is peculiar in its internal structure, which, together with the structure of guard hairs in this species, confirms its phylogenetically distinct position within Ctenohystrica. For the compared species, the complex medulla is with variously arranged systems of keratinized septa and different degrees of development of air spaces between them (ranging from unstructured and irregular to uni- or biserial ladder-like, cellated or pyramidal). The vibrissae have a non-specialized cuticle serving mostly for protection during tactile contacts, which distinguishes it from the diverse and multifunctional cuticle of guard hairs, spines, and quills. The tactile function of vibrissae is corroborated by the presence of scuff marks, scratches and even cuticle loss at the tip and on the ventral side of the rod, a thickened dense cortex and a poorly developed medullar layer but diverse its internal architecture, which provides only a very limited thermal protection, unlike that of the hair pelage. The SEM study of vibrissal architecture is a promising line of research, because a better knowledge of vibrissae may contribute to the biology and biomimetics.

394. USEFULNESS OF INTRAOPERATIVE RECURRENT LARYNGEAL NERVE MONITORING IN REDUCING RECURRENT LARYNGEAL NERVE PARALYSIS AFTER ROBOT-ASSISTED THORACOSCOPIC ESOPHAGECTOMY

Abstract Background Robot-assisted thoracoscopic esophagectomy (RAMIE) is a precise and safe procedure with its advantages. On the other hand, RAMIE has several disadvantages. The lack of tactile function must be fully recognized, and surgical procedures must take the characteristics into account. We examined whether the findings obtained by intraoperative recurrent nerve monitoring (NIM) are useful in reducing recurrent laryngeal nerve paralysis (RLNP) after RAMIE. Methods Overall, 81 cases of RAMIE through February 2023 were included in the study. NIM was performed in 41 patients in the first term using a combination of continuous and intermittent methods (NIM group). In the subsequent 40 patients, NIM was not performed (non-NIM group) in order to confirm the learning effect of NIM and to shorten the operation time. RLNP was confirmed by a combination of symptoms and postoperative laryngoscopy. Clinical and oncological factors and short-term outcomes of the two groups were compared. Results All postoperative RLNP occurred on the left side. Six patients (14.6%) in the NIM group had Grade 1 or higher RLNP. The causes of RLNP were all found during thoracic manipulation; 4 cases of over-traction of RLN and 2 cases of crush injury by robotic forceps. There was a significant decrease in RLNP of Grade 2 or higher; 4 patients (9.7%) in the NIM group and 0 in the non-NIM group (p = 0.04). In the non-NIM group, there was a reduction in thoracic operative time, total operative time, and thoracic blood loss. Conclusion NIM made us aware of surgical maneuvers that cause RLNP after RAMIE. Although the proficiency of the RAMIE technique may have played a role in the reduction of RLNP in the later period, avoidance of risky surgical procedures due to the learning effect from the NIM was thought to have contributed to the decrease in RLNP.

A protocol for tactile function assessment using JVP domes: Feasibility study and preliminary results.

Touch is a crucial sense for perceiving the spatial characteristics of objects. The JVP dome was developed to evaluate tactile spatial acuity using a grating orientation task. There were few studies depicting sequences and details for the entire task, including practice, training, and testing sessions. Therefore, we proposed and elaborated a protocol for the grating orientation task using the staircase method, which required fewer testing trials compared with the method of constant stimuli. Twenty-three healthy participants were enrolled in this experiment. The JVP domes with 11 different groove widths were used. Tactile discrimination thresholds were estimated using a two-down-one-up staircase method. The experiment comprised practice, training, and testing sessions, conducted by trained examiners who performed grating stimulation on participants' index fingerpads. All participants passed the required accuracy in the practice and training sessions. Eight transition points were obtained in the testing session for each participant. The tactile discrimination thresholds were determined from the last six transition points. We obtained the mean tactile discrimination threshold as 1.8±0.75mm (n=23). The results demonstrated that the proposed protocol was successfully applied to assess tactile discrimination thresholds. The present study investigated the protocol of grating orientation tasks requiring a small number of testing trials with the assurance of the task quality. The feasibility study and preliminary results indicated the potentiality of this protocol for future clinical application.

A multimode‐fused sensory memory system based on a robust self‐assembly nanoscaffolded BaTiO3:Eu2O3 memristor

AbstractBiologically inspired neuromorphic sensory memory systems based on memristor have received a lot of attention in the booming artificial intelligence industry due to significant potential to effectively process multi‐sensory signals from complex external environments. However, many memristors have significant switching parameters disperse, which is a great challenge for using memristors in bionic neuromorphic sensory memory systems. Herein, a stable ferroelectric memristor based on the Pd/BaTiO3:Eu2O3/La0.67Sr0.33MnO3 grown on Silicon structure with SrTiO3 as buffer layer is presented. The device possesses low coercive field voltage (−1.3–2.1 V) and robust endurance characteristic (~1010 cycles) through optimizing the growth temperature. More importantly, an ultra‐stable artificial multimodal sensory memory system with visual and tactile functions was reported for the first time by combining a pressure sensor, a photosensitive sensor, and a robotic arm. Utilizing the above system, the sensitivity value of the system is expressed by the conductance of the memristor to realize the gradual change of external stimulus, and multi signals inputs at the same time to this system have faithfully achieved sensory adaptation to multimodal sensors. This work paves the way for future development of memristor‐based perception systems in efficient multisensory neural robots.image

Composites Based on Cotton Microfibers Impregnated with Magnetic Liquid for Magneto-Tactile Sensors.

In this paper, we report the preparation of two new composite materials based on cotton fibers and magnetic liquid consisting of magnetite nanoparticles and light mineral oil. Using the composites and two simple textolite plates plated with copper foil assembled with self-adhesive tape, electrical devices are manufactured. By using an original experimental setup, we measured the electrical capacitance and the loss tangent in a medium-frequency electric field superimposed on a magnetic field. We found that in the presence of the magnetic field, the electrical capacity and the electrical resistance of the device change significantly with the increase of the magnetic field, then, the electrical device is suitable to be used as a magnetic sensor. Furthermore, the electrical response functions of the sensor, for fixed values of the magnetic flux density, change linearly with the increase in the value of the mechanical deformation stress, which gives it a tactile function. When applying mechanical stresses of fixed values, by increasing the value of the magnetic flux density, the capacitive and resistive functions of the electrical device change significantly. So, by using the external magnetic field, the sensitivity of the magneto-tactile sensor increases, therefore the electrical response of this device can be amplified in the case of low values of mechanical tension. This makes the new composites promising candidates for the fabrication of magneto-tactile sensors.

Mixed-Dimensional MXene Nanocomposites/Aramid Nanofibers-Based Flexible Pressure and Strain Sensor for Electronic Skin

The implementation of tactile functions in array sensors has created an urgent need for high-performance force sensors with both high linearity and sensitivity so as to ensure the uniformity and accuracy of acquisition of multiple sensing units in the array sensors. In addition, it still remains challenging to fabricate exquisite geometric constructions for integrating highly sensitive materials, extraordinary sensitivity, high stretchability, wide sensing range, and flexibility into a single type of pressure/strain sensor. Herein, a sensitive flexible sensor was fabricated that was composed of mixed-dimensional MXene-based nanocomposites as piezoresistive layers and Ecoflex layers as the encapsulation. The resultant sensors with MXene (Ti3C2Tx)-ANF (aramid nanofiber)-BP (black phosphorus)-gold (Au) nanocomposites exhibited excellent electrical conductivity, ultrahigh press sensitivity of 0.4986 kPa–1 (0–1 kPa), reliable linearity (R2 = 0.998), rapid response time of 12 ms, excellent durability over 4000 cycles, and ultrahigh tensile sensitivity of 9188.583. An 8 × 8 pixel electronic skin was fabricated by the as-prepared mixed-dimensional MXene-based sensors and tested in the identification of sliding movements and surface shape, and the good performance shows great potential applications in the fields of wearable devices, human–machine interaction, and robotics.

Feasibility, Validity, and Reliability of Lower Limb Tactile and Body Awareness Assessments in Children With Upper Motor Neuron Lesions

ObjectiveTo investigate the feasibility, discriminative and convergent validity, and inter-rater reliability of a lower limb tactile function and 2 body awareness assessments in children with upper motor neuron (UMN) lesions. DesignCross-sectional psychometric study. SettingPediatric rehabilitation center. ParticipantsForty individuals with UMN lesions (mean age 11.7 years, SD 3.4 years; 27 girls) and 40 neurotypically developing children of the same age participated (N=80). InterventionsNot applicable. Main Outcome MeasuresWe assessed the tactile threshold (TT) with monofilaments and body awareness with tactile localization tasks (TLTs) for structural (TLTaction) and spatial (TLTperception) body representation at the foot sole. We compared the test outcomes between children with UMN lesions and neurotypically developing children with the Wilcoxon signed-rank test. Furthermore, we quantified the relations between the 3 tests with Spearman correlations (rs) and the interrater reliability with quadratic weighted kappa (κQW). ResultsAbout 80% of the children with UMN lesions perceived the tests easy to perform. The children with UMN lesions had significantly reduced somatosensory function compared with the neurotypically developing children. For the more affected leg, we found good relations between the TT and the TLTaction (rs=0.71; P<.001) and between the 2 TLTs (rs=0.66; P<.001), and a fair relation between the TT and the TLTperception (rs=0.31; P=.06). The inter-rater reliability analyses for the sum scores showed almost perfect agreement for the TT (κQW more affected leg 0.86; less affected leg 0.81), substantial agreement for TLTaction (κQW more affected leg 0.76; less affected leg 0.63), and almost perfect agreement for TLTperception (κQW more affected leg 0.88; less affected leg 0.74). ConclusionThe 3 tests are feasible to assess lower limb somatosensory function in children with UMN lesions. Discriminative and convergent validity and reliability of the 3 tests were confirmed. Further studies should investigate responsiveness and association with motor function of these outcome measures.

Gustation in insects: taste qualities and types of evidence used to show taste function of specific body parts.

The insect equivalent of taste buds are gustatory sensilla, which have been found on mouthparts, pharynxes, antennae, legs, wings, and ovipositors. Most gustatory sensilla are uniporous, but not all apparently uniporous sensilla are gustatory. Among sensilla containing more than one neuron, a tubular body on one dendrite is also indicative of a taste sensillum, with the tubular body adding tactile function. But not all taste sensilla are also tactile. Additional morphological criteria are often used to recognize if a sensillum is gustatory. Further confirmation of such criteria by electrophysiological or behavioral evidence is needed. The five canonical taste qualities to which insects respond are sweet, bitter, sour, salty, and umami. But not all tastants that insects respond to easily fit in these taste qualities. Categories of insect tastants can be based not only on human taste perception, but also on whether the response is deterrent or appetitive and on chemical structure. Other compounds that at least some insects taste include, but are not limited to: water, fatty acids, metals, carbonation, RNA, ATP, pungent tastes as in horseradish, bacterial lipopolysaccharides, and contact pheromones. We propose that, for insects, taste be defined not only as a response to nonvolatiles but also be restricted to responses that are, or are thought to be, mediated by a sensillum. This restriction is useful because some of the receptor proteins in gustatory sensilla are also found elsewhere.

Oral Somatosensory Alterations in Head and Neck Cancer Patients-An Overview of the Evidence and Causes.

Food-related sensory alterations are prevalent among cancer patients and negatively impact their relationship with food, quality of life, and overall health outcome. In addition to taste and smell, food perception is also influenced by somatosensation comprising tactile, thermal, and chemesthetic sensations; yet studies on oral somatosensory perception of cancer patients are lacking to provide patients with tailored nutritional solutions. The present review aimed to summarise findings on the oral somatosensory perception of head and neck cancer (HNC) patients and the potential aetiologies of somatosensory alterations among this population. Subjective assessments demonstrated alterations in oral somatosensory perception such as sensitivity to certain textures, spices, and temperatures. Physiological changes in oral somatosensation have been observed through objective assessments of sensory function, showing reduced localised tactile function and thermal sensitivity. Changes in whole-mouth tactile sensation assessed using texture discrimination and stereognosis ability seem to be less evident. Available evidence indicated oral somatosensory alterations among HNC patients, which may affect their eating behaviour, but more studies with larger sample sizes and standardised assessment methods are needed. Unlike other types of cancers, sensory alterations in HNC patients are not only caused by the treatments, but also by the cancer itself, although the exact mechanism is not fully understood. Prevalent oral complications, such as xerostomia, dysphagia, mucositis, and chemosensory alterations, further modify their oral condition and food perception. Oral somatosensory perception of cancer patients is an under-investigated topic, which constitutes an important avenue for future research due to its potential significance on eating behaviour and quality of life.

In situ Simulation of Thermal Reality.

Simulated reality encompasses virtual, augmented, and mixed realities-each characterized by different degrees of truthfulness in the visual perception: "all false," "coexistence of true and false," and "difficult distinction between true and false," respectively. In all these technologies, however, the temperature rendering of virtual objects is still an unsolved problem. Undoubtedly, the lack of thermal tactile functions substantially reduces the quality of the user's real-experience perception. To address this challenge, we propose theoretically and realize experimentally a technological platform for the insitu simulation of thermal reality. To this purpose, we design a thermal metadevice consisting of a reconfigurable array of radiating units, capable of generating the thermal image of any virtual object, and thus rendering it insitu together with its thermal signature. This is a substantial technological advance, which opens up new possibilities for simulated reality and its applications to human activities.

Evaluation in Ayres Sensory Integration® (EASI) Tactile Perception Tests: Construct Validity and Internal Reliability

Assessment of tactile perception is foundational for addressing aspects of occupational performance. To evaluate the construct validity and internal reliability of four new tactile perception tests. Causal comparative groups design. Homes, schools, and therapy practices across the United States. Children ages 3 to 12 yr: typically developing (n = 174) and those with sensory integration concerns (n = 153). Rasch analyses to evaluate construct validity; analysis of covariance to evaluate group differences. The Rasch model confirmed evidence of construct validity for each of the four tests. The typically developing group scored significantly higher than the clinical group on all tests (η2p = .040-.105, p < .001). Person reliability indices and strata indicated moderate to strong internal reliability (Rasch person reliability indices = .69-.87; strata = 2.33-3.82). The Evaluation in Ayres Sensory Integration® (EASI) Tactile Perception Tests are reliable and valid measures for assessing tactile perception in children ages 3 to 12 yr. Findings suggest that these tests are likely to be clinically useful and appropriate for children in this age range and may provide critical information regarding underlying sensory functions necessary for optimal occupational performance. What This Article Adds: This article provides data supporting the reliability and validity of the EASI Tactile Perception Tests in a U.S. These assessments can be used by therapists trained in their administration to assess tactile functions that may affect participation in activities, tasks, and occupations.

Thermal Nociception of Ionic Skin: TRPV1 Ion Channel-Inspired Heat-Activated Dynamic Ionic Liquid

The artificial reproduction of the tactile sensory function of natural skin is crucial for intelligent sensing, human-computer interaction, and medical health. Thermal nociception is an essential human tactile function to avoid noxious thermal stimuli, which depends on the specific heat-activation of the TRPV1 ion channel. Inspired by the TRPV1, a dynamic ionic liquid with heat-activation characteristics is designed and prepared, which can be activated at 45 °C, which is near the physiological noxious temperature, accompanied by a steep rise in electrical response signals. Its electrical behavior can be deemed to be the extreme version of temperature sensation similar to the natural thermal nociceptor. The heat-activation mechanism is confirmed as a feasible strategy to regulate the thermal response behavior of ions, and this reported dynamic ionic liquid has an unprecedented intrinsic temperature response sensitivity of up to 156.79%/°C. In consideration of the similarity between the heat-activated dynamic ionic liquid and the TRPV1 ion channel in terms of heat-activation characteristics, electrical output signal, and ultrathermal sensitivity, an all-liquid ionic skin with the ability of thermal nociception is further fabricated, which shows considerable potential to assist patients with tactile desensitization to avoid noxious thermal stimuli.

Research advances on the function of skin touch receptor Merkel cells

The reconstruction of tactile function during the repair of skin damage caused by factors including burns is inseparable from the functional regeneration of tactile receptor Merkel cells. Merkel cells mainly exist in the basal layer of the epidermis and are closely connected with nerves to form Merkel cell-nerve complexes, which play an important role in biological organisms. A large number of studies have shown that Merkel cells conduct precise transmission of mechanical force stimuli through the mechanically gated ion channels PIEZO2, and perform the function of tactile receptors. In this paper, we discussed the characteristics of Merkel cells and analyzed the different subgroups that may possibly exist in this type of cells and their functions, at the same time, we investigated the animal model research of touch-related diseases and the clinical diseases related to touch, revealing the importance of Merkel cell function research.