Tag Archives: #touch

Sight through Touch: The Secret Is in the Hand Movements (Neuroscience)

Recreating the “feel” of an object as participants move their fingers enables them to use their ingrained sensing strategies

Vision and touch employ a common strategy: To make use of both these senses, we must actively scan the environment. When we look at an object or scene, our eyes continuously survey the world by means of tiny movements; when exploring an object by touch, we move the tips of our fingers across its surface. Keeping this shared feature in mind, Weizmann Institute of Science researchers have designed a system that converts visual information into tactile signals, making it possible to “see” distant objects by touch.  

Converting information obtained with one sense into signals perceived by another – an approach known as sensory substitution – is a powerful means of studying human perception, and it holds promise for improving the lives of people with sensory disabilities, particularly the blind. But even though sensory substitution methods have been around for more than fifty years, none have been adopted by the blind community for everyday use.

(l-r) Prof. Ehud Ahissar, Dr. Amos Arieli, and Dr. Yael Zilbershtain-Kra. At the tips of their fingers © Weizmann Institute of Science and Technology

The Weizmann researchers assumed that the main obstacle has been the fact that most methods are incompatible with our natural perception strategies. In particular, these methods leave out the component referred to as active sensing. Thus, most vision-to-touch systems make finger movement unnecessary by converting the visual stimuli to vibratory skin stimulations.

Dr. Amos Arieli and Prof. Ehud Ahissar of the Neurobiology Department, together with intern Dr. Yael Zilbershtain-Kra, set themselves the goal to develop a vision-to-touch system that would more closely mimic the natural sense of touch. The idea was to enable the user to perceive information by actively exploring the environment, without the confusing intervention of artificial stimulation aids.

“Our system not just enables but, in fact, forces people to perform active sensing – that is, to move a hand in order to ‘see’ distant objects, much as they would to palpate a nearby object,” Arieli says. “The sensation occurs in their moving hand, as in regular touch.”

In the Weizmann system – called ASenSub – a small lightweight camera is attached to the user’s hand, and the image it captures is converted into tactile signals via an array of 96 pins placed under the tips of three fingers of the same hand. After the camera’s frame is mapped onto the pins, the height of each pin is determined by the brightness of the corresponding pixel in the frame. For example, if the camera scans a black triangle on a white surface, the pins corresponding to white pixels stay flat, while those mapped to black pixels are raised the moment the camera meets the triangle, producing a virtual feeling of palpating an embossed triangle.

In the ASenSub system, a special converter (1) creates tactile signals on the basis of visual information captured by a small camera (2) © Weizmann Institute of Science and Technology

Zilbershtain-Kra, with the help of ophthalmologist Dr. Shmuel Graffi, tested ASenSub in a series of experiments with sighted, blindfolded, participants and with people blind from birth. Both groups were at first asked to identify two-dimensional geometrical shapes, then three-dimensional objects, such as an apple, a toy rhinoceros and a pair of scissors. 

Following training of less than two and a half hours, both groups learned to identify objects correctly within less than 20 seconds – an unprecedented level of performance compared with existing vision-to-touch methods, which generally require lengthy training and enable perception that remains frustratingly slow. No less significant was the fact that the high performance was preserved over a long period: Participants invited for another series of experiments nearly two years later were quick to identify new shapes and objects using ASenSub.

“Our approach has demonstrated the brain’s amazing plasticity, which, in a way, enabled people to acquire a new ‘sense'”

In the triple array of pins sensed by the tips of three fingers (right), the raised pins (black) represent a black triangle captured by the camera © Weizmann Institute of Science and Technology

Yet another striking quality of ASenSub: It gave blind-from-birth participants a true “feel” for what it’s like to see objects at a distance. Says Graffi: “As a clinician, it was fascinating for me that they could actually experience optical properties they’d previously only heard about, such as shadows or the reduced size of distant objects.”

Sighted and blind participants performed equally well in the experiments, but analysis of results showed that their scanning strategies were different. Sighted people tended to focus to a great extent on the object’s unique feature, for example, the tip of the triangle, the rhino’s tale or scissor blades. In contrast, blind people encompassed each object along its entire contour, much as they commonly do to identify objects by unaided touch.

In other words, people relied on a strategy that’s most familiar to them through experience, which suggests that it’s learning and experience that mainly guide us in the use of our senses, rather than some inborn, genetically preprogrammed property of the brain. And this conclusion, in turn, suggests that in the future, it may be possible to teach people with sensory disabilities to make more optimal use of their senses.

“In broader terms, our study provides further support for the idea that natural sensing is primarily active,” Ahissar says. “We let people be active and to do so in an intuitive way, using their automatic perceptual systems that work with closed loop interactions between the brain and the world. This is what likely led to dramatic improvement compared to other vision-to-touch methods.” Zilbershtain-Kra adds: “Our approach has demonstrated the brain’s amazing plasticity, which, in a way, enabled people to acquire a new ‘sense.’ After seeing how fast they acquired a new perception method via active sensing, I’ve started applying similar principles when teaching students – making sure that they stay active throughout the learning process.”

The ASenSub system may be used for further fundamental studies of human perception, and it can be applied for daily use by the blind. For the latter purpose, it needs to be scaled down to a miniature device that can be worn as a glove or incorporated into a walking cane.

Science Numbers

Compared to other existing methods, the perceptional accuracy and speed of identifying both 2- and 3-D objects in the system that converts visual information into tactile signals, based on “active sensing”, have improved on average by 300% and 600% respectively.

Featured image: Yellow and red, showing the most frequently scanned areas, reveal the differences in scanning strategies employed by the sighted people (left) and the blind (right) while using ASenSub © Weizmann Institute of Science and Technology

Provided by Weizmann Institute of Science

Fingerprints Enhance Our Sense of Touch (Neuroscience)

Sensory neurons in the finger can detect touch on the scale of a single fingerprint ridge

Fingerprints may be more useful to us than helping us nab criminal suspects: they also improve our sense of touch. Sensory neurons in the finger can detect touch on the scale of a single fingerprint ridge, according to new research published in JNeurosci.

The hand contains tens of thousands of sensory neurons. Each neuron tunes in to a small surface area on the skin — a receptive field — and detects touch, vibration, pressure, and other tactile stimuli. The human hand possesses a refined sense of touch, but the exact sensitivity of a single sensory neuron has not been studied before.

To address this, Jarocka et al. measured the electrical activity of the sensory neurons in human fingertips when they stimulated with raised dots swept over the skin. The research team calculated the detection areas of the sensory neurons and mapped them onto the fingerprints. The width of the detection areas matched the width of a single fingerprint ridge. These areas stayed on the same fingerprint ridges during different scanning speeds and directions, indicating that they are anchored to the fingerprint ridges. The overlap of receptive fields with small detection areas explains how humans have such a sensitive and accurate sense of touch.

Featured image: Receptive fields of sensory neurons in the hand, mapped onto a fingertip. © Jarocka et al., JNeurosci 2021

Paper title: Human Touch Receptors Are Sensitive To Spatial Details on the Scale of Single Fingerprint Ridges

Provided by Society for Neuroscience

Soft Robots Use Camera And Shadows To Sense Human Touch (Engineering)

Soft robots may not be in touch with human feelings, but they are getting better at feeling human touch.

Cornell researchers have created a low-cost method for soft, deformable robots to detect a range of physical interactions, from pats to punches to hugs, without relying on touch at all. Instead, a USB camera located inside the robot captures the shadow movements of hand gestures on the robot’s skin and classifies them with machine-learning software.

The group’s paper, “ShadowSense: Detecting Human Touch in a Social Robot Using Shadow Image Classification,” published Dec. 17 in the Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies. The paper’s lead author is doctoral student Yuhan Hu.

The new ShadowSense technology is the latest project from the Human-Robot Collaboration and Companionship Lab, led by the paper’s senior author, Guy Hoffman, associate professor and the Mills Family Faculty Fellow in the Sibley School of Mechanical and Aerospace Engineering.

“Touch is such an important mode of communication for most organisms, but it has been virtually absent from human-robot interaction. One of the reasons is that full-body touch used to require a massive number of sensors, and was therefore not practical to implement,” Hoffman said. “This research offers a low-cost alternative.”

Video: Cornell researchers have created a low-cost method for soft, deformable robots to detect a range of physical interactions, from pats to punches to hugs, without relying on touch at all. © Cornell University

The technology originated as part of a collaboration with Hadas Kress-Gazit, professor in the Sibley School of Mechanical and Aerospace Engineering, and Kirstin Petersen, assistant professor of electrical and computer engineering, to develop inflatable robots that could guide people to safety during emergency evacuations. Such a robot would need to be able to communicate with humans in extreme conditions and environments. Imagine a robot physically leading someone down a noisy, smoke-filled corridor by detecting the pressure of the person’s hand.

Rather than installing a large number of contact sensors – which would add weight and complex wiring to the robot, and would be difficult to embed in a deforming skin – the team took a counterintuitive approach. In order to gauge touch, they looked to sight.

“By placing a camera inside the robot, we can infer how the person is touching it and what the person’s intent is just by looking at the shadow images,” Hu said. “We think there is interesting potential there, because there are lots of social robots that are not able to detect touch gestures.”

The prototype robot consists of a soft inflatable bladder of nylon skin stretched around a cylindrical skeleton, roughly four feet in height, that is mounted on a mobile base. Under the robot’s skin is a USB camera, which connects to a laptop. The researchers developed a neural-network-based algorithm that uses previously recorded training data to distinguish between six touch gestures – touching with a palm, punching, touching with two hands, hugging, pointing and not touching at all – with an accuracy of 87.5 to 96%, depending on the lighting.

The robot can be programmed to respond to certain touches and gestures, such as rolling away or issuing a message through a loudspeaker. And the robot’s skin has the potential to be turned into an interactive screen.

By collecting enough data, a robot could be trained to recognize an even wider vocabulary of interactions, custom-tailored to fit the robot’s task, Hu said.

The robot doesn’t even have to be a robot. ShadowSense technology can be incorporated into other materials, such as balloons, turning them into touch-sensitive devices.

“While the technology has certain limitations, for example requiring a line of sight from the camera to the robot’s skin, these constraints could actually spark a new approach to social robot design that would support a visual touch sensor like the one we proposed,” Hoffman said. “In the future, we would like to experiment with using optical devices such as lenses and mirrors to enable additional form factors.”

In addition to providing a simple solution to a complicated technical challenge, and making robots more user-friendly to boot, ShadowSense offers a comfort that is increasingly rare in these high-tech times: privacy.

“If the robot can only see you in the form of your shadow, it can detect what you’re doing without taking high fidelity images of your appearance,” Hu said. “That gives you a physical filter and protection, and provides psychological comfort.”

The ability to physically interact and understand a person’s movements and moods could ultimately be just as important to the person as it is to the robot.

“Touch interaction is a very important channel in terms of human-human interaction. It is an intimate modality of communication,” Hu said. “And that’s not easily replaceable.”

The paper was co-authored by former research intern Sara Maria Bejarano of the University of Los Andes, Colombia.

The research was supported by the National Science Foundation’s National Robotic Initiative.

Reference: Yuhan Hu, Sara Maria Bejarano, and Guy Hoffman. 2020. ShadowSense: Detecting Human Touch in a Social Robot Using Shadow Image Classification. Proc. ACM Interact. Mob. Wearable Ubiquitous Technol. 4, 4, Article 132 (December 2020), 24 pages. DOI:https://doi.org/10.1145/3432202

Provided by Cornell University

All in the Mind: Is Reality Real? (Philosophy)

Why the way we experience and interact with the world is entirely mind-made

Saltatory conduction is the process through which the brain receives information from the five sense organs, which include the eyes, ears, nose, tongue, and skin. When sense receptors in the sense organs are stimulated, electrochemical impulses travel via a process of neurotransmission from the peripheral nervous system to the central nervous system. Once received by the central nervous system, these electrochemical messages culminate in the brain where they are transformed into coherent information that can be acted upon.

Saltatory conduction was first identified in 1939 by Japanese born American biophysicist Ichiji Tasaki, and scientific understanding of the process has increased significantly since that time. However, although the mechanisms of this fundamental biological process are well documented, it appears that some important implications of saltatory conduction have been overlooked in the scientific literature – particularly in terms of how it can advance understanding of how we perceive reality.

More specifically, saltatory conduction provides evidence indicating that the reality we perceive and experience on a day-to-day basis is far less real or concrete than collective opinion might suggest. The reason for this is that without exception, our sense of movement, touch, taste, pain, pleasure, sight, sound, and so forth are the product of the brain filtering, transforming and organising electrochemical information into a working three-dimensional mental construction.

For example, when we look at a tree, what we see is the brain’s interpretation of electrochemical signals that were transmitted by sensory receptors in the eyes. Consequently, our perception of the tree isn’t “direct” but is the end product of a biophysical process involving receiving, transforming, transmitting and then retransforming information. The same applies if we reach out and touch the tree – we experience the brain’s reconstruction, based on input from electrochemical signals, of how it interprets the tree should feel to the hand.

A good way to understand this principle is to consider how information is processed using Voiceover Internet Protocol that underlies web-based video calling platforms such as Messenger, Skype and WhatsApp. In such instances, a caller’s camera and microphone capture analogue video and audio signals which are then compressed and transformed into digital numeric packets. These data packets are then transmitted over a digital network before being decompressed and transformed back to analogue video images and audio sounds by the recipient’s video conferencing system. However, at no point can it be said that the two callers’ interaction with each other is unmodified and direct, as their video call is subject to various stages of data transformation and transportation.

A similar type of “data transformation” process occurs during saltatory conduction such that in reality, we never directly touch, smell, see, hear, or taste sensory phenomena. Consequently, although we have the impression of living in and moving through a physical world, we never truly go anywhere or do anything because at any given time, our experience of life corresponds to the mental projection of the brain. In other words, the manner by which we experience and interact with the world is entirely mind-made – we project a reality and then relate to it entirely within the realm of the mind.

Consider the analogy of a dream whereby the dreamer is invariably under the impression that what they are experiencing is real. For example, when dreaming, individuals can have the sensation of coming or going, pleasure or pain, and fast or slow. In fact, an individual can experience a dream as being real to the extent that it causes them to wake up screaming if the dream is sufficiently frightening. However, although the dream may appear real, in truth it has no material existence and unfolds completely within the expanse of the mind. In a dream, nothing really comes or goes, there is no here or there, no near or far, no up or down, and no fast or slow.

However, it’s not correct to assert that what we experience during dreamt or waking reality is unreal, because regardless of whether a phenomenon or situation exists in material absolute terms or is just a fabrication of the mind, we still undergo an authentic experience. Indeed, the extent to which a given experience is designated as authentic or meaningful is highly subjective and varies according to context and how the mind has been conditioned.

Nevertheless, it appears that as part of some fundamental biological processes such as saltatory conduction, there exists evidence suggesting a need to re-examine the accuracy of certain widely accepted scientific assumptions concerning the underlying nature of mind and matter. Perhaps through fostering a better understanding of the inseparability between mind and matter in this manner, new psychological and technological approaches will emerge that better enable humans to harness resources and benefit from both their psychological and physical world.

References: (1) Shonin, E., & Van Gordon, W. (2014). Dream or reality? Philosophy Now, 104, 54 (2) Soeng, M. (1995). Heart Sutra: Ancient Buddhist Wisdom in the Light of Quantum Reality. Cumberland: Primary Point Press. (3) Van Gordon, W., Sapthiang, S., Barrows, P., & Shonin, E. (2020). Understanding and practicing emptiness. Mindfulness, Advance Online Publication, DOI: 10.1007/s12671-020-01586-1 (4) Van Gordon, W., Shonin, E., Dunn, T., Sapthiang, S., Kotera, Y., Garcia-Campayo, J., & Sheffield, D. (2019). Exploring emptiness and its effects on non-attachment, mystical experiences, and psycho-spiritual wellbeing: A quantitative and qualitative study of advanced meditators. Explore: The Journal of Science and Healing, 15, 261-272. (5) Vogel, H. (2009). Nervous System: Cambridge Illustrated Surgical Pathology. New York: Cambridge University Press. (6) Wireless Research Centre (n.d.). How Voice and Video Call Works? Available from: https://danenet.wicip.org/2019/04/23/how-voice-and-video-call-works/

Copyright of this article totally belongs to Dr. William Van Gordon, who is a Chartered Psychologist and Associate Professor of Contemplative Psychology at the University of Derby (UK). This article is republished here from psychology today under common creative licenses

The Power of Touch (Psychology)

New research shows the benefits of affectionate touch, even for those who think they don’t need it.

The Japanese have a word that they believe they borrowed from English, but you won’t find it in any dictionary. When the Japanese use this word, they’re referring to the importance of touch in close relationships. They call this skinship, that is, a relationship built on and nurtured by skin-to-skin contact.

“Skinship” doesn’t just refer to the intimate touch of sexual partners. Rather, it also includes family members and even some friends as well. Babies and small children, in particular, need a lot of skinship time with their caregivers, but we all need some skin-to-skin contact with those who are close to us.

The Japanese understand intuitively what Western psychologists have only come to realize after extensive research—namely that affectionate touch is a powerful way to communicate intimacy in close relationships. The frequency of affectionate touch is associated with both physical and psychological well-being, and those who are deprived of it suffer from depression, anxiety, and a host of other maladies.

Nevertheless, there are persons who recoil from physical contact with others, even those close to them. These people also report more psychological problems than the general population. Perhaps this is because they unwittingly deprive themselves of the affectionate touch they need. But it could also be that physical contact has the opposite effect on them, increasing psychological discomfort rather than alleviating it. This is the issue that University of Lausanne (Switzerland) psychologist Anik Debrot and colleagues explored in a study they recently published in the Personality and Social Psychology Bulletin.

Debrot and colleagues first consider the role of attachment style in intimate relationships. Attachment style refers to your way of interacting with your romantic partner during times of stress, and it first develops in infancy through exchanges with your caregiver. Infants who learn that their mothers will reliably meet their needs develop a secure attachment style, and as adults, they are generally trusting of others, especially intimates.

In contrast, infants who learn that their caregivers don’t reliably meet their needs will develop one of two different types of insecure attachment styles. Some develop an anxious attachment style, in which they’re extremely fussy in order to capture their mother’s attention. As adults, they’re clingy and demanding, and they frequently worry that their lovers will abandon them.

Other infants develop an avoidant attachment style, whereby they learn to self-soothe. As adults, they prize their independence, and they feel uncomfortable getting too close in intimate relationships. These are the people who feel little desire for physical contact outside of sex, and they dread the affectionate touches and hugs that others try to inflict upon them.

Debrot and colleagues’ research question was straightforward: Do people with avoidant attachment style recoil from touch because it provides them no psychological good or even harms them? Or might they benefit from touch just as much as others do if only they could overcome their deep reluctance to engage in physical contact with intimates?

To explore these questions, the researchers conducted three separate studies. The first was a survey of more than 1,600 individuals who were in an intimate relationship. Questions asked about attachment style, well-being, and touch behaviors, including types (caressing, cuddling, kissing, and so on) and frequency (ranging from never to four or more times a day).

The results showed, as expected, that people who touched their partners more frequently also reported higher levels of well-being. Furthermore, as expected, those with an avoidant attachment style generally indicated less frequent physical contact with their partner, and they also exhibited lower levels of well-being. However, some avoidantly attached individuals claimed that they did touch their partner often, and these persons enjoyed levels of well-being similar to others who reported frequent physical contact.

This last finding suggests that persons with an avoidant attachment style can benefit from intimate touch just as others do, and at any rate, it certainly doesn’t harm them. However, we always need to be wary when interpreting the data from self-reports such as these. So, to further explore the connection between avoidant attachment and the benefits of touch, Debrot and colleagues invited 66 couples to visit their lab.

When they arrived at the lab, the couples individually responded to surveys about attachment style, well-being, and touch similar to those in the first study. They were then asked to engage in a series of conversations with each other about times they had made a sacrifice for their partner or felt strong love for their partner. These conversations were recorded, and afterward, observers counted the number of times they touched each other. The participants also indicated their level of positive feeling before and after each conversation.

The results of this second study were similar to those of the first. But one new finding was that a high frequency of touching during a difficult conversation didn’t necessarily boost positive feelings right away. Rather, the researchers speculate that it’s the general pattern of touching in the relationship that leads to higher levels of well-being overall.

The third study was a 28-day diary study consisting of 98 couples in which each partner reported attachment style on the first day and then noted positive mood and touch behaviors on a daily basis thereafter. The results confirmed the findings of the two previous studies, but in addition, it provided new information about the impact of attachment style on the partner. That is to say, not only did those individuals with an avoidant attachment style report lower levels of positive mood, so did their partners.

However, avoidantly attached individuals who were receptive to their partner’s touch advances generally reported higher levels of positive mood. This clearly indicates that physical contact is beneficial even for those who tend to pull back when significant others try to touch. Thus, Debrot and colleagues suggest that therapists develop techniques for helping those with an avoidant attachment style to overcome their aversion to non-sexual physical contact.

Most people are comforted by the “skinship” connections they have with intimate partners and close family members. Yet people with an avoidant attachment style tend to recoil from physical contact, even though it would do them good if only they were open to it.

Although attachment style is set in childhood, there’s plenty of evidence that it can change in adulthood. This is especially true when you can develop enough self-awareness to know your attachment style, and if you have a partner who is supportive of your personal growth.

References: Debrot, A., Stellar, J. E., MacDonald, G., Keltner, D., & Impett, E. A. (2020). Is touch in romantic relationships universally beneficial for psychological well-being? The role of attachment avoidance. Personality and Social Psychology Bulletin. Advance online publication. DOI: 10.1177/0146167220977709

This article is republished here from psychology today under common creative licenses

When It Comes to Feeling Pain, Touch or an Itch, Location Matters (Neuroscience)

When you touch a hot stove, your hand reflexively pulls away; if you miss a rung on a ladder, you instinctively catch yourself. Both motions take a fraction of a second and require no forethought. Now, researchers at the Salk Institute have mapped the physical organization of cells in the spinal cord that help mediate these and similar critical “sensorimotor reflexes.”

The researchers studied the organization of interneurons in the spinal cord, like those shown here. Credit: Salk Institute

The new blueprint of this aspect of the sensorimotor system, described online in Neuron on November 11, 2020, could lead to a better understanding of how it develops and can go awry in conditions such as chronic itch or pain.

“There’s been a lot of research done at the periphery of this system, looking at how cells in the skin and muscles generate signals, but we didn’t know how that sensory information is trafficked and interpreted once it reaches the spinal cord,” says Martyn Goulding, a professor in Salk’s Molecular Neurobiology Laboratory and holder of the Frederick W. and Joanna J. Mitchell Chair. “This new work gives us a fundamental understanding of the architecture of our sensorimotor system.”

Reflexive behaviors—seen even in newborn babies—are considered some of the simplest building blocks for movement. But reflexes must quickly translate information from sensory neurons that detect touch, heat and painful stimuli to motor neurons, which cause the muscles to take action. For most reflexes, the connections between the sensory neurons and motor neurons are mediated by interneurons in the spinal cord, which serve as sort of “middlemen,” thereby saving time by bypassing the brain. How these middlemen are organized to encode reflexive actions is poorly understood.

Goulding and his colleagues turned to a set of molecular engineering tools they’ve developed over the past decade to examine the organization of these spinal reflexes in mice. First, they mapped which interneurons were active when mice responded reflexively to sensations, like itch, pain or touch. They then probed the function of interneurons by turning them on and off individually and observing how the resulting reflex behaviors were affected.

Graphical abstract by Goulding et al.

“What we found is that each sensorimotor reflex was defined by neurons in the same physical space,” says postdoctoral researcher Graziana Gatto, the first author of the new paper. “Different neurons in the same place, even if they had very different molecular signatures, had the same function, while more similar neurons located in different areas of the spinal cord were responsible for different reflexes.”

Interneurons in the outermost layer of the spinal cord were responsible for shuttling reflexive messages related to itch between sensory and motor cells. Deeper interneurons relayed messages of pain—causing a mouse to move a foot touched by a pin, for instance. And the deepest set of interneurons helped mice reflexively keep their balance, stabilizing their body to prevent falling. But within each spatial area, neurons had varying molecular properties and identities.

“These reflexive behaviors have to be very robust for survival,” says Goulding. “So, having different classes of interneurons in each area that contribute to a particular reflex builds redundancy into the system.”

By demonstrating that the location of each interneuron type within the spinal cord matters more than the cell’s developmental origin or genetic identity, the team tested and confirmed an existing theory about how these reflex systems are organized.

Now that they know the physical architecture of the interneuron circuits that make up these different reflex pathways, the researchers are planning future studies to reveal how messages are conveyed and how the neurons within each space interact with each other. This knowledge is now being used to probe how pathological changes in the somatosensory system result in chronic itch or pain. In an accompanying paper, Gatto and Goulding collaborated with Rebecca Seal of the University of Pittsburgh to map the organization of neurons that generate different forms of chronic pain.

Reference: Graziana Gatto et al, A Functional Topographic Map for Spinal Sensorimotor Reflexes, Neuron (2020). https://linkinghub.elsevier.com/retrieve/pii/S0896627320307716 DOI: 10.1016/j.neuron.2020.10.003

Provided by Salk Institute

Fingerprints Moisture-regulating Mechanism Strengthens Human Touch (Biology)

Human fingerprints have a self-regulating moisture mechanism that not only helps us to avoid dropping our smartphone, but could help scientists to develop better prosthetic limbs, robotic equipment and virtual reality environments, a new study reveals.

Fingerprints’ moisture mechanism could be boon to robotics experts © University of Birmingham

Primates – including humans, monkeys and apes – have evolved epidermal ridges on their hands and feet with a higher density of sweat glands than elsewhere on their bodies. This allows precise regulation of skin moisture to give greater levels of grip when manipulating objects.

Fingerprints help to increase friction when in contact with smooth surfaces, boost grip on rough surfaces and enhance tactile sensitivity. Their moisture-regulating mechanism ensures the best possible hydration of the skin’s keratin layer to maximise friction.

Researchers at the University of Birmingham worked with partners at research institutions in South Korea, including Seoul National University and Yonsei University – publishing their findings today in Proceedings of the National Academy of Sciences (PNAS).

Co-author Mike Adams, Professor in Product Engineering and Manufacturing, at the University of Birmingham commented: “Primates have evolved epidermal ridges on their hands and feet. During contact with solid objects, fingerprint ridges are important for grip and precision manipulation. They regulate moisture levels from external sources or the sweat pores so that friction is maximised and we avoid ‘catastrophic’ slip and keep hold of that smartphone.”

“Understanding the influence of finger pad friction will help us to develop more realistic tactile sensors – for example, applications in robotics and prosthetics and haptic feedback systems for touch screens and virtual reality environments.”

Ultrasonic lubrication is commonly used in touch screen displays that provide sensory ‘haptic’ feedback, but its effectiveness is reduced when a user has dry compared with moist finger pads. Moreover, being able to distinguish between fine-textured surfaces, such as textiles, by touch relies on the induced lateral vibrations but the absence of sliding friction inhibits our ability to identify what we are actually touching.

Fingerprints are unique to primates and koalas – appearing to have the dual function of enhancing evaporation of excess moisture whist providing a reservoir of moisture at their bases that enables grip to be maximised.

The researchers have discovered that, when finger pads are in contact with impermeable surfaces, the sweat from pores in the ridges makes the skin softer and thus dramatically increases friction. However, the resulting increase in the compliance of the ridges causes the sweat pores eventually to become blocked and hence prevents excessive moisture that would reduce our ability to grip objects.

Using hi-tech laser-based imaging technology, the scientists found that moisture regulation could be explained by the combination of this sweat pore blocking and the accelerated evaporation of excessive moisture from external wetting as a result of the specific cross-sectional shape of the epidermal furrows when in contact with an object.

These two functions result in maintaining the optimum amount of moisture in the fingerprint ridges that maximises friction whether the finger pad is initially wet or dry.

“This dual-mechanism for managing moisture has provided primates with an evolutionary advantage in dry and wet conditions – giving them manipulative and locomotive abilities not available to other animals, such as bears and big cats,” added Professor Adams.

Reference: Seoung-Mok Yum, In-Keun Baek, Dongpyo Hong, Juhan Kim, Kyunghoon Jung, Seontae Kim, Kihoon Eom, Jeongmin Jang, Seonmyeong Kim, Matlabjon Sattorov, Min-Geol Lee, Sungwan Kim, Michael J. Adams, Gun-Sik Park, “Fingerprint ridges allow primates to regulate grip”, Proceedings of the National Academy of Sciences Nov 2020, 202001055; DOI: 10.1073/pnas.2001055117 https://www.pnas.org/content/early/2020/11/24/2001055117

Provided by University of Birmingham

Notes to editors:

* The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, teachers and more than 6,500 international students from over 150 countries.
* ‘Fingerprint ridges allow primates to regulate grip’ – Seoung-Mok Yum, In-Keun Baek, Dongpyo Hong, Juhan Kim, Kyunghoon Jung, Seontae Kim, Kihoon Eom, Jeongmin Jang, Seonmyeong Kim, Matlabjon Sattorov, Min-Geol Leed, Sungwan Kime, Michael J. Adams and Gun-Sik Parka is published in Proceedings of the National Academy of Sciences (PNAS)

Ultrathin Nanomesh Sensor to Measure Sense of touch (Neuroscience)

World’s first fingertip-mounted sensor that maintains user’s sensitivity.

Scientists from the Technical University of Munich (TUM) and the University of Tokyo have developed an ultrathin pressure sensor that can be attached directly to the skin. It can measure how fingers interact with objects to produce valuable data for technological or medical applications. The sensor has an unnoticeable effect on the users’ sensitivity and ability to grip objects, and it is highly resistant to disruption from rubbing.

The ultrathin nanomesh sensor has an unnoticeable effect on the users’ sensitivity and ability to grip objects. Image: Someya-Yokota-Lee Group / The University of Tokyo

Our hands and fingers are our primary tools for direct interaction with materials, other human beings and our immediate environment. Finding out how the sense of touch actually works and having ways to record it would be a great benefit not only for research in the fields of medicine, sports or neuroengineering, but also for archiving skills.

However, capturing this data is not easy. A wearable sensor on a finger has to be extremely thin and flexible, because fingertips are so sensitive that anything could affect the feeling. In addition, a sensor worn on hands needs to be resistant to rubbing or other physical damage.

To overcome this problem, David Franklin, Professor for Neuromuscular Diagnostics at TUM and his colleagues teamed up with researchers from the University of Tokyo. Here, a group of scientists led by Professor Takao Someya had developed a sensor covered by four ultrathin layers of a functional and porous material named “nanomesh sensor”, which “turned out to be just perfect”, as Franklin says.

Thinner than a human hair

A layer of polyurethane nanofibers serves as a passivation and carrier layer. This is followed by an ultra-thin layer of gold mesh, an intermediate layer of parylene-coated polyurethane nanofibers and finally another layer of gold mesh. A thin top-layer of polyurethane and polyvinyl alcohol nanofibers mechanically protects the four layers of the sensor.

“Both nanomesh layers were made by a process called electro spinning,” Someya says. The polyurethane fibers are between 200 to 400 nanometers thick, about two hundreds the thickness of a human hair.

The other two layers are a stencil-like network of lines that form the functional electronic component of the sensor. They are made from gold and use a supporting frame of polyvinyl alcohol, a polymer which is also used for contact lenses. After the manufacturing process, the polymer is washed away to leave only the gold traces it was supporting.

Minimal effect on sensitivity

The researchers performed a rigorous set of tests on the sensors with the help of 18 participants. All of them confirmed that the sensors were imperceptible and affected neither the ability to grip objects through friction, nor the perceived sensitivity compared to performing the same task without a sensor attached. This was exactly the result the researchers were looking for.

“In the past, we only had relatively rigid measuring instruments that interfere with the sense of touch” Franklin says. “Think about your pet at home, perhaps your cat or dog. Which instrument is both soft and sensitive enough to measure how much pressure you use when caressing it? Until now this was impossible, but with this new nanomesh sensor applied on our fingers we suddenly can.”

Designed to archive knowledge of any delicate work

One way the novel applications could be used is the digital archiving of delicate craftwork by artisans. “Let’s say you want to study how to make a handcrafted watch,” says Franklin. “How could we capture the ability of the incredible talented watchmakers for posterity? We would like to know how they actually pick up and manipulate the tiny pieces while building the watch. By applying the ultrathin nanomesh sensor on the fingertips, we could measure the force and record it without influencing the finger’s sense of touch.”

In fact, this is the first time in the world that a fingertip-mounted sensor with no effect on skin sensitivity has been successfully demonstrated. And the sensor maintained its performance as a pressure sensor even after being rubbed against a surface with a force equivalent to atmospheric pressure, 300 times without breaking, the scientists discovered. “This shows that we can actually measure the manipulation of a huge range of objects – this has never been possible before.”

References: Sunghoon Lee, Sae Franklin, Faezeh Arab Hassani, Tomoyuki Yokota, Md Osman Goni Nayeem, Yan Wang, Raz Leib, Gordon Cheng, David W. Franklin, Takao Someya:
Nanomesh pressure sensor for monitoring finger manipulation without sensory interference. Science, Vol. 370, Issue 6519, pp. 966-970, 2020. DOI: 10.1126/science.abc9735

Provided by TUM

Can Touch Heal? (Psychology)

For over 40 years, I have practiced the integration of bodywork and psychotherapy as a clinician licensed in both disciplines. I have pioneered the integration of these methods at the Harvard Medical School Department of psychiatry in 1985 and have worked with over 60,000 clients. The application of these therapies is most effective when tailored to the needs of each individual and to their specific stage of recovery.


Massage and bodywork decrease depression and anxiety; they were used in children with PTSD following Hurricane Andrew (Field, Seligman, Scafidi, & Schanberg, 1996), in female survivors of sexual abuse (Field, et al., 1997; Price, 2005, 2007), and in dementia caregivers with a history of trauma (Korn et al., 2009). Several studies and metastudies have demonstrated efficacy for massage and bodywork for the treatment of fibromyalgia (Cao, Liu, & Lewith, 2010; Kalichman, 2010; Sunshine et al., 1996).

Massage is used extensively along with psychotherapy for the treatment of torture victims at rehabilitation centers around the world; it often comprises a special massage of the galea, a band of muscle around the head, for relief of the headaches common to nearly all torture victims (Bloch, 1988). Complementary forms of touch physiotherapy are practiced at rehabilitation centers throughout Europe with a focus on specific physical injuries; it includes body awareness methods that help the torture victim to accept his or her body again (Ortmann, Genefke, Jakobsen, & Lunde, 1987). 

During the 1960s, the early pioneering work of biologist Bernard Grad, a student of the body-oriented psychoanalyst Wilhelm Reich, measured changes in the growth of plants and bacteria in response to the “laying on of hands.” Since then, numerous studies have measured functional alterations in brainwaves, heart rhythm, and hormone levels in response to direct touch or nonlocal “touch” or intention within healer and “healer.” Among the biofield, touch therapies are methods called therapeutic touch, Reiki, healing touch, and the light touch of polarity therapy. They all appear to reduce sympathetic activity (Cox & Hayes, 1999; Gehlhaart, 2000; Rowlands, 1984) by stimulating the vagal response. Biofield therapies also lead to a reduction in pain (Sansone & Schmitt, 2000), anxiety (Gagne & Toye, 1994), cancer-related fatigue (Roscoe, Matteson, Mustian, Padmanaban, & Morrow, 2005), quality of life (Metz, 1992), and depression (Field, 2000; Rowlands, 1984; Wardell & Engebretson, 2001). These therapies have, furthermore, been found to increase energy (Lee et al., 2001) and mood and improve sleep (Smith, Stallings, Mariner, & Burrall, 1999).


How does touch heal?

  • Touch arouses, desensitizes, and transduces state-dependent memory; it also facilitates consciousness states associated with alpha, beta, theta, and delta brainwaves.
  • Touch can induce trance and simultaneously provide the grounding rod to gain control over dissociative processes.
  • Touch is anxiolytic and soporific; it also stimulates circulatory, lymphatic, and immune responses and regulates the primary respiratory mechanism (the cranial-sacral rhythm).
  • Touch activates assorted neurohormonal responses, including the release of beta-endorphins, oxytocin, and serotonin; it improves cortisol levels and stimulates the endocannabinoid system.
  • Touch provides a nonverbal form of biofeedback, allowing for the simultaneous retrieval of somatosensory memory, body sensations, articulation of associative feelings, and cognitive reframing.
  • Touch changes body image and improves body concept, including the exploration of kinesthetic and proprioceptive boundaries as it reduces autonomic hyperactivity.
  • Touch reduces lactic acid, thereby reducing the chemistry feedback loop of anxiety.
  • Touch facilitates somatic empathy, a psychobiological attunement that is a prerequisite for attachment and bonding.
  • Touch alters favorably the subtle human biofields that are the foundation of the healthy functioning of the human organism.

Therapeutic forms of massage and touch therapies like Polarity therapy, cranial-sacral therapies can be used alone or integrated into the psychotherapeutic model if the individual is trained and licensed to practice both therapies. It then is often called Body Oriented psychotherapy or somatic psychotherapy.

References: (1) Smith, M. C., Stallings, M. A., Mariner, S., & Burrall, M. (1999). Benefi ts of massage therapy for hospitalized patients: A descriptive and qualitative evaluation. Alternative Therapy for Health Medicine, 5 (4), 64–71. (2) Lee, M. S., Yang, K. H., Huh, H. J., Kim, H. W., Ryu, H., Lee, H. S., & Chung, H. T. (2001). Qi therapy as an intervention to reduce chronic pain and to enhance mood in elderly subjects: A pilot study. American Journal of Chinese Medicine, 29 (2), 237–245. (3) Field T. (2000). Touch therapy. London: Churchill Livingstone. (4) Metz, R. (1992). Application of magnetic and polarity principles to life energy systems. Santa Rosa, CA: Author. (5) Roscoe, J., Matteson, S., Mustian, K. M., Padmanaban, D., & Morrow, G. R. (2005). Treatment of radiotherapy-induced fatigue through a nonpharmacological approach. Integrated Cancer Therapy, 4 (1), 8–13. (6) Gagne, D., & Toye, R. (1994). The effects of therapeutic touch and relaxation therapy in reducing anxiety. Archives of Psychiatric Nursing, 8 (3), 184–189. (7) Sansone, P., & Schmitt, L. (2000). Providing tender touch massage to elderly nursing home residents: A demonstration project. German Nursing, 21 (6), 303–308. (8) Cox, C., & Hayes, J. (1999). Physiologic and psychodynamic responses to the administration of therapeutic touch in critical care. Complementary Therapies in Nursing and Midwifery, 5 (3), 87–92. (9) Ortmann, J., Genefke, I. K., Jakobsen, L., & Lunde, I. (1987). Rehabilitation of torture victims: An interdisciplinary treatment model. American Journal of Social Psychiatry, 7 (4), 161–167. (10) Bloch, I. (1988). Physiotherapy and the rehabilitation of torture victims. Clinical Management in Physical Therapy, 8 (3), 26–29. (11) Cao, H., Liu, J., & Lewith, G. T. (2010). Traditional Chinese medicine for the treatment of fibromyalgia: A systematic review of randomized controlled trials. Journal of Alternative and Complementary Medicine, 16(4), 397–409. (12) Korn, L., Logsdon, R. G., Polissar, N. L., Gomez-Beloz, A., Waters, T., & Rÿser, R. (2009). A randomized trial of a CAM therapy for stress reduction in American Indian and Alaskan Native family caregivers. Gerontologist, 49 (3), 368–377. (13) Field, T., Hernandez-Reif, M., Hart, S., Quintino, O., Drose, L., Field, T., Schanberg, S. (1997). Effects of sexual abuse are lessened by massage therapy. Journal of Bodywork and Movement Therapies, 1 (2), 65–69. (14) Field, T., Seligman, S., Scafi di, F., & Schanberg, S. (1996). Alleviating posttraumatic stress in children following Hurricane Andrew. Journal of Applied Developmental Psychology, 17 (1), 37–50.

This article is republished here from psychology today under common creative licenses.