Tactile Sensory Systems Research Articles

Tactile sensory synapse based on organic electrochemical transistors with ionogel triboelectric layer

Recent advancements in artificial tactile sensory systems have significantly improved their ability to replicate the sensory functions of biological systems by integrating various sensory and synaptic components, yet these configurations often lack the efficiency and seamless integration seen in nature. To address these limitations, we introduce a monolithic artificial mechanoreceptor that combines an organic electrochemical transistor with an ionogel (IG), serving as both a mechano-responsive triboelectric sensing layer and a gate electrolyte. Triboelectrification upon mechanical stimulation using different materials produces an output voltage of the triboelectric generator which drives the movement of ions within the tribo-negative IG based on 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid and poly(vinylidene fluoride-co-hexafluoropropylene), modulating de-doping of the poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) channel. This enhances synaptic functionalities such as spike number-dependent plasticity (SNDP) and spike duration-dependent plasticity (SDDP) during mechanical stimulation, allowing the device to mimic biological mechanoreceptors by sensing and converting external mechanical signals, including the number, force, and duration of touches, into synaptic plasticity. Furthermore, the device shows potential for material recognition using machine learning techniques, marking a significant advancement towards efficient artificial tactile systems.

Recent Advances in Tactile Sensory Systems: Mechanisms, Fabrication, and Applications.

Flexible electronics is a cutting-edge field that has paved the way for artificial tactile systems that mimic biological functions of sensing mechanical stimuli. These systems have an immense potential to enhance human-machine interactions (HMIs). However, tactile sensing still faces formidable challenges in delivering precise and nuanced feedback, such as achieving a high sensitivity to emulate human touch, coping with environmental variability, and devising algorithms that can effectively interpret tactile data for meaningful interactions in diverse contexts. In this review, we summarize the recent advances of tactile sensory systems, such as piezoresistive, capacitive, piezoelectric, and triboelectric tactile sensors. We also review the state-of-the-art fabrication techniques for artificial tactile sensors. Next, we focus on the potential applications of HMIs, such as intelligent robotics, wearable devices, prosthetics, and medical healthcare. Finally, we conclude with the challenges and future development trends of tactile sensors.

Recent Advances in Smart Tactile Sensory Systems with Brain‐Inspired Neural Networks

Tactile sensory systems play a vital role in various emerging fields including robotics, prosthetics, and human–machine interfaces. However, traditional tactile sensors are typically designed to detect a single stimulus through a lock‐and‐key mechanism, which poses substantial challenges in the realization of multimodal tactile sensors. To address this issue, the convergence of tactile sensory systems with artificial neural network and machine learning (ML) platforms has been utilized to enhance the capabilities of multimodal sensors and enable signal decoupling/interpretation of mixed tactile stimuli. Herein, recent progress in multimodal sensors that can simultaneously identify various stimuli such as strain, pressure, and temperature is reviewed, providing in‐depth understanding of materials, structures, and methodologies. In addition, accurate interpretation of signals from mixed tactile stimuli under complex conditions remains challenging. This review presents a comprehensive exploration of ML algorithms that mimic human neural networks, discussing their significance in advancing smart sensory systems and improving signal interpretation in complex and dynamic environments.

Stretchable Transistor-Structured Artificial Synapses for Neuromorphic Electronics.

Stretchable synaptic transistors, a core technology in neuromorphic electronics, have functions and structures similar to biological synapses and can concurrently transmit signals and learn. Stretchable synaptic transistors are usually soft and stretchy and can accommodate various mechanical deformations, which presents significant prospects in soft machines, electronic skin, human-brain interfaces, and wearable electronics. Considerable efforts have been devoted to developing stretchable synaptic transistors to implement electronic device neuromorphic functions, and remarkable advances have been achieved. Here, this review introduces the basic concept of artificial synaptic transistors and summarizes the recent progress in device structures, functional-layer materials, and fabrication processes. Classical stretchable synaptic transistors, including electric double-layer synaptic transistors, electrochemical synaptic transistors, and optoelectronic synaptic transistors, as well as the applications of stretchable synaptic transistors in light-sensory systems, tactile-sensory systems, and multisensory artificial-nerves systems, are discussed. Finally, the current challenges and potential directions of stretchable synaptic transistors are analyzed. This review presents a detailed introduction to the recent progress in stretchable synaptic transistors from basic concept to applications, providing a reference for the development of stretchable synaptic transistors in the future.

A Novel Nociceptor Functional Circuit for Tactile Applications

In this research, the main functional characteristics of nociceptors are considered for designing a novel neuromorphic circuit in TSMC 180 nm CMOS technology with a 1.8 V supply voltage and 780 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> power consumption. Indeed, the current study is the first analog circuit realization of the functional model of nociceptors. The proposed circuit includes three spiking neurons. The first and second neurons determine the pressure level and the active area of the stimulus, respectively. The pressure to active area ratio is sensed by the third neuron and helps for better discrimination of the input stimuli. To evaluate the performance of the proposed nociceptor circuit, we perform numerical simulations and robotic experiments. In this way, the 3D-printed objects with different sharpness are touched by a custom-made tactile sensor and the spiking responses from the nociceptor neuromorphic circuit are then collected. Next, machine learning algorithms are applied offline to classify objects based on the rate and time of the spike responses. The results show that by analyzing the spike patterns obtained from the bio-inspired circuit, it is possible to recognize stimuli after the emission of a few spikes. The proposed approach is the proof of concept that circuit implementation of the functional model of the nociceptors expands the range of object recognition and hence facilitates the fabrication of novel tactile sensory systems for bio-robotic and prosthetic applications.

Visual and Tactile Sensory Systems Share Common Features in Object Recognition.

Although we use our visual and tactile sensory systems interchangeably for object recognition on a daily basis, little is known about the mechanism underlying this ability. This study examined how 3D shape features of objects form two congruent and interchangeable visual and tactile perceptual spaces in healthy male and female participants. Since active exploration plays an important role in shape processing, a virtual reality environment was used to visually explore 3D objects called digital embryos without using the tactile sense. In addition, during the tactile procedure, blindfolded participants actively palpated a 3D-printed version of the same objects with both hands. We first demonstrated that the visual and tactile perceptual spaces were highly similar. We then extracted a series of 3D shape features to investigate how visual and tactile exploration can lead to the correct identification of the relationships between objects. The results indicate that both modalities share the same shape features to form highly similar veridical spaces. This finding suggests that visual and tactile systems might apply similar cognitive processes to sensory inputs that enable humans to rely merely on one modality in the absence of another to recognize surrounding objects.

MXenes for memristive and tactile sensory systems

One of the most effective approaches to solving the current problem arising from the von Neumann bottleneck in this period of data proliferation is the development of intelligent devices that mimic the human learning process. Information sensing and processing/storage are considered to be the essential processes of learning. Therefore, high-performance sensors, memory/synaptic devices, and relevant intelligent artificial tactile perception systems are urgently needed. In this regard, innovative device concepts and emerging two-dimensional materials have recently received considerable attention. Herein, we discuss the development of MXenes for applications in tactile sensors, memristors, and artificial tactile perception systems. First, we summarize the structures, common properties, and synthesis and assembly techniques of MXenes. We then discuss the applications of MXenes in tactile sensors, memristors, and relevant neuromorphic-based artificial tactile perception systems along with the related working mechanisms. Finally, we present the challenges and prospects related to MXene synthesis, assembly, and application.

Deep Neural Network Classification of Tactile Materials Explored by Tactile Sensor Array With Various Active-Cell Formations

Reducing the input data of tactile sensory systems brings a large degree of freedom to real-world implementations from the perspectives of bandwidth and computational complexity. For this, in this letter, we suggest efficient active-cell formations with a high classification accuracy of tactile materials. By revealing that averaged Kullback–Leibler-divergence and common frequency component power to variance ratio are proportional to the classification accuracy, we showed that those methods can be useful in estimating valid active-cell formations.

Biomimetic Tactile Sensors Based on Nanomaterials.

Tactile sensor technology has been researched extensively in response to the increasing demand for robotic and wearable healthcare systems. Studies on tactile sensory systems have primarily focused on achieving two goals: (1) developing technologies with high sensing abilities that mimic the biological functions and characteristics of the sensory systems of human skin and (2) satisfying the requirements of wearable device applications by fabricating mechanically flexible devices with low-power data analysis and processing abilities. In this Perspective, we present recent advances in artificial tactile sensory systems, which are based on biomimetic technologies that exhibit functional features of biological systems including mechanoreceptors and human skin sensory neurons for human-machine interfaces. We also discuss the opportunities, current challenges, potential solutions, and future investigative directions pertaining to this field.

EFFECTS OF SENSORY INTEGRATION THERAPY ON SELECTED FITNESS SKILLS IN AUTISTIC CHILDREN

Introduction: Autism is a pervasive developmental disorder characterised by abnormal development in the first two years of life and impairment with respect to the following three areas: social interactions, communication, and behaviour. The disorder is more common in males than females. The aim: The study was conducted to assess the effects of sensory integration therapy on selected fitness skills in autistic children. Material and methods: The study assessed a group of 20 children (15 boys and 5 girls) aged 3 to 10 years. All children were diagnosed with autism and underwent 2-year therapy. The children showed impaired sensory modulation with abnormal stimulus reception and processing in the tactile, auditory, vestibular (balance), olfactory, and gustatory sensory systems. The study assessed fitness skills and their correlations with sensory integration therapy used in the children. The assessment used the Sensorimotor Development Questionnaire developed by Zbigniew Przyrowski and selected tests from "Obserwacja Kliniczna" as well as history-taking conducted with the parents. The following aspects were analysed: muscle tone, static balance, dynamic balance, jumping on two legs, jumping on one leg, catching and throwing a ball, and self-care activities, such as putting on shoes. Results: Sensory integration therapy contributed to an improvement in motor, sensory, cognitive, emotional, communication, and social development in the study patients. Conclusion: The use of sensory integration effectively supports sensory processes in autistic children.

Neural Foundations of Ayres Sensory Integration®.

Sensory integration, now trademarked as Ayres Sensory Integration® or ASI, is based on principles of neuroscience and provides a framework for understanding the contributions of the sensory and motor foundations of human behavior. The theory and practice of ASI continues to evolve as greater understanding of the neurobiology of human behavior emerges. In this paper we examine core constructs of ASI identified in the seminal work of Dr. Jean Ayres, and present current neuroscience research that underlies the main patterns of sensory integration function and dysfunction. We consider how current research verifies and clarifies Ayres’ propositions by describing functions of the vestibular, proprioceptive, and tactile sensory systems, and exploring their relationships to ocular, postural, bilateral integration, praxis, and sensory modulation. We close by proposing neuroplasticity as the mechanisms underlying change as a result of ASI intervention.

A study to assess the effectiveness of swaddling on pain among neonates undergoing heel lancing procedure in neonatal intensive care units

Neonates, infants and children often require examinations and investigations for admissions in the hospital. Even after admission frequent examinations and procedures will be carried out for further management. Pain during such investigations, treatments and procedures are called as procedural pain.1Appropriate pain relief can be achieved through administration of analgesics. But analgesics can cause different side effects and reaction to the newborns.2 Swaddling is the procedure of wrapping a baby in a blanket for warmth and security.3 swaddling provides stimulation across the proprioceptive, thermal, and tactile sensory systems that may reduce pain through gate control mechanisms.4

Magic Room: A Smart Space for Children with Neurodevelopmental Disorder

The Magic Room is a smart space for use by children with neurodevelopmental disorder (NDD) and their caregivers designed in cooperation with NDD specialists and currently deployed at two therapeutic centers in Italy. It supports multimodal embodied interaction by providing controllable stimuli to the vestibular, proprioceptive, and tactile sensory systems through ambient sound and visual projections, soap bubbles, aromas, lights, toys and other physical objects. Results of an exploratory study involving 8 caregivers and 19 children with severe NDD impairments who used the Magic Room for four months are encouraging and might pave the way for new research and inspire novel interventions in this area.

ВПЛИВ НА ПРИЙНЯТТЯ РІШЕНЬ СПОЖИВАЧІВ НА РИНКУ ТУРИСТИЧНИХ ПОСЛУГ ЗА ДОПОМОГОЮ ТЕХНОЛОГІЙ НЕЙРОМАРКЕТИНГУ

The constant renewal and growth of the number of tourism destinations and types of tourist services, changing consumer preferences, increasing competition in the market force us to turn to innovative marketing technologies, as traditional ones lose their effectiveness. Given the fact that tourists often choose a travel package with a unique set of services, as an important aspect of travel for people are emotions, impressions, and unique feelings, the study chose psychological methods, techniques, technologies, and tools of neuromarketing (neural marketing) to involve consumers in the market of tourist services by influencing their behavior. In particular, the article focuses on theoretical and applied aspects of the use of neuromarketing technologies to influence consumer decision-making in the travel services market through the impact on visual, auditory, olfactory, gustatory, and tactile sensory systems. It was found that marketers, in particular in the field of tourism, most often use visual and auditory methods of influence, but now is becoming increasingly popular aroma marketing and marketing of taste, which affects the sense of smell and taste buds. All these methods affect the associative memory of a person and this further helps to create a permanent customer base and attract new consumers. Attention is paid to highlighting the specifics of the influence of color or a certain combination of colors on the human subconscious. A set of tools and technologies of neuromarketing are used in tourism to attract attention, change the mood of the tourist, and evoke the right emotions, including such as illustrations, music, flavor, taste, the atmosphere of restaurants, tastings, and others. Based on the study of the peculiarities of the use of neuromarketing (sensory marketing) technologies in tourism, the authors identified several benefits that help attract new customers and encourage them to make purchases.

Rubber Hand Illusion: Evidence for a multisensory integration of proprioception

La presente revisión tiene como objetivo describir una hipótesis de integración multisensorial para la propiocepción a través de la descripción de distintos configuraciones experimentales con la Ilusión de la Mano de Goma (img). img es un paradigma creado en 1998 para explorar la relación entre los sistemas sensoriales visual y táctil. La tarea implica una estimulación síncrona de una mano de los sujetos, oculto de su visión, y una mano de goma en frente del sujeto. Instruidos para mirar la mano de goma, después de aproximadamente medio minuto, el sujeto comienza a sentir la mano de goma como su propia mano. La ilusión produce un sentimiento de propiedad de la mano de goma. La literatura ha investigado ampliamente el experimento en los últimos 15 años, demostrando las funciones dinámicas de los sistemas sensoriales del cerebro y del cuerpo, así como clarificando aspectos de la rehabilitación de sujetos amputados y diferentes tipos de parestesia. La revisión se estructura en torno de tres temas: (1) definición de la img, sus límites y alcances, (2) evidencias fisiológicas y neurocognitivas que dan apoyo a la img, y (3) la img en configuraciones experimentales implicando acción. La revisión concluye que la img es un ejemplo práctico de una tendencia neurocientífica innovadora para el estudio integrado del cuerpo, el cerebro y el espacio perceptual. La ilusión también ha establecido una forma alternativa para el estudio de la propiocepción y la dinámica del cerebro en sujetos normales

Speed Matching Interaction between Visual and Tactile Motion

The goal of the present study is to explore the speed discrimination interaction between visual and tactile motion during unimodal tasks and crossmodal tasks. Fifteen participants performed four speed reproduction tasks that included a tactile-tactile task, a visual-visual task, a tactile-visual task and a visual-tactile task at various speeds. Participants were asked to remember the standard stimuli speed and match the stimuli speed with the standard stimuli speed. The present study showed that both visual discrimination speed and tactile visual discrimination are underestimated relative to the standard speed at relatively high speeds during unimodal tasks. The present study suggests that speed matching is processed similarly in both the visual and tactile sensory systems. Moreover, the present study demonstrated reciprocal interactions between the processing of visual speed matching and tactile speed matching. Visual speed stimuli positively affected tactile speed matching, whereas tactile speed stimuli disrupted visual speed matching at relatively high speeds. Interestingly, visual speed stimuli can calibrate the tactile speed discrimination, but not vice-versa. A possible explanation is that the perceptual system is organized such that speed stimuli input from visual modalities receive a higher weight in the interaction process than speed stimuli input from tactile modalities. The reciprocal interactions between visual and tactile speed matching modalities directly support the view that at some point in the motion processing stream, these two modalities have partially overlapping substrates. Keywords: Crossmodal, speed matching, tactile speed, unimodal, visual speed.

The intraoral tactile reception and its interaction with the gustatory system in fish

The oral cavity in mammals and humans is a zone where tactile senses are considered to be basic and fre� quently evoked [1]. However, the intraoral tactile reception in fish has been poorly investigated. It is sug� gested that the food texture is a complex combination of mechanical characteristics, including hardness, plasticity, and firmness of the object. Its viscosity and fluidity, roughness of the surface, etc., along with taste properties, can be decisive for fish when swallowing or rejecting food objects [2, 3]. Data that can confirm this suggestion are scanty, and most of them are qualitative and demonstrate a selective consumption of food items with low hardness by fish [4–9]. The depen� dence of consumption on the texture properties of food items has been poorly studied, and the character of this dependence when both tactile and gustatory receptors in the oral cavity of fish are stimulated simultaneously is unknown. However, precisely this multisensory assessment of the food completes com� plex feeding behavior and regulates the feeding in fish and other animals. The interaction of tactile and gus� tatory systems occurs at any level from the periphery to brain centers [10], and the information provided by these sensory systems is mutually complimentary [11]. The aim of this study was to estimate the effect of the texture of the food object on its attractiveness for fish and the possibility of its modification by adding of taste substances. For the first time it has been demon� strated that the increase in the mechanical hardness of food results in the decrease of its consumption by fish. This dependence is more expressed when food items consumed by fish have a strong taste. The results testify to the participation of both tactile and gustatory intraoral contact sensory systems in the regulation of food consumption in fish. The role of each sensory system is determined by mechanic and chemosensory (gustatory) characteristics of the food object. The experiments were conducted in 13 individuals of carp with lengths of 12.4 cm and body weight of 21.3 g. We placed the fish, one by one, in aquaria (10 L) and then introduced experimental pellets of 4 mm in length and 1.35 mm in diameter to fish. The pellets were cut out from agar gel of 1, 2, 3, 4 and 5% concen� trations. All pellets had red colour by the adding of dye Ponceau 4R (5 µM) to the gel. In the trials the control p <

Chemical Basis of Prey Recognition in Thamnophiine Snakes: The Unexpected New Roles of Parvalbumins

Detecting and locating prey are key to predatory success within trophic chains. Predators use various signals through specialized visual, olfactory, auditory or tactile sensory systems to pinpoint their prey. Snakes chemically sense their prey through a highly developed auxiliary olfactory sense organ, the vomeronasal organ (VNO). In natricine snakes that are able to feed on land and water, the VNO plays a critical role in predatory behavior by detecting cues, known as vomodors, which are produced by their potential prey. However, the chemical nature of these cues remains unclear. Recently, we demonstrated that specific proteins–parvalbumins–present in the cutaneous mucus of the common frog (Rana temporaria) may be natural chemoattractive proteins for these snakes. Here, we show that parvalbumins and parvalbumin-like proteins, which are mainly intracellular, are physiologically present in the epidermal mucous cells and mucus of several frog and fish genera from both fresh and salt water. These proteins are located in many tissues and function as Ca2+ buffers. In addition, we clarified the intrinsic role of parvalbumins present in the cutaneous mucus of amphibians and fishes. We demonstrate that these Ca2+-binding proteins participate in innate bacterial defense mechanisms by means of calcium chelation. We show that these parvalbumins are chemoattractive for three different thamnophiine snakes, suggesting that these chemicals play a key role in their prey-recognition mechanism. Therefore, we suggest that recognition of parvalbumin-like proteins or other calcium-binding proteins by the VNO could be a generalized prey-recognition process in snakes. Detecting innate prey defense mechanism compounds may have driven the evolution of this predator-prey interaction.

Effects of facilitated swaddling for controlling procedural pain in premature neonates: a randomized controlled trial

Preterm neonates are exposed to multiple painful medical interventions in neonatal intensive care units (NICU) but pain assessment and control remains suboptimal. Facilitated swaddling, as a pain relief intervention, has been studied among full term and healthy infants, however little attention has been given to premature neonates. We investigated the effect of facilitated swaddling to control procedural pain among premature neonates. 54 premature neonates between 30–36 6/7 gestation age from NICU were randomly assigned to facilitated swaddling (N=27) and control (no intervention, N=27). Written informed consent was obtained from a parent. Assessment of pain was performed pre, during, immediate, 2, 4, 6, and 8 minutes after heelstick procedure using the Premature Infant Pain Profile (PIPP). The PIPP is a composite measure of seven indicators including heart rate (HR) and oxygen saturation (SaO2), three facial responses to pain, behavioral state and gestational age. It has demonstrated high level of reliability and validity. The results showed that the mean PIPP scores were significantly reduced in the intervention compared to the control group (during, immediate, 2, 4, and 6 minutes after heelstick procedure) (P=0.001). The mean HR and SaO2 in the intervention group were significantly lower than that of the control group at all measured time points (P<0.001). Notably, both HR and SaO2 of the swaddled neonates resumed to the baseline level at 2 minutes whereas the physiologic outcomes of the control group reached the stable state at an extended period of 6 to 8 minutes respectively. These results suggest that facilitated swaddling was effective in controlling procedural pain of heelstick among premature neonates. No adverse effects were observed. It has been suggested that the motor containment provides stimulation across the proprioceptive, thermal and tactile sensory systems that may reduce pain through gate control mechanisms.

Audiotactile interactions in temporal perception

In the present review, we focus on how commonalities in the ontogenetic development of the auditory and tactile sensory systems may inform the interplay between these signals in the temporal domain. In particular, we describe the results of behavioral studies that have investigated temporal resolution (in temporal order, synchrony/asynchrony, and simultaneity judgment tasks), as well as temporal numerosity perception, and similarities in the perception of frequency across touch and hearing. The evidence reviewed here highlights features of audiotactile temporal perception that are distinctive from those seen for other pairings of sensory modalities. For instance, audiotactile interactions are characterized in certain tasks (e.g., temporal numerosity judgments) by a more balanced reciprocal influence than are other modality pairings. Moreover, relative spatial position plays a different role in the temporal order and temporal recalibration processes for audiotactile stimulus pairings than for other modality pairings. The effect exerted by both the spatial arrangement of stimuli and attention on temporal order judgments is described. Moreover, a number of audiotactile interactions occurring during sensory-motor synchronization are highlighted. We also look at the audiotactile perception of rhythm and how it may be affected by musical training. The differences emerging from this body of research highlight the need for more extensive investigation into audiotactile temporal interactions. We conclude with a brief overview of some of the key issues deserving of further research in this area.