Program > Keynotes

Keynote speakers

Sliman Bensmaia (4 July morning)

James and Karen Frank Family Professor, Department of Organismal Biology and Anatomy, University of Chicago, USA

Biological and Bionic Hands: Natural Neural Coding and Artificial Perception

Our ability to manipulate objects dexterously relies fundamentally on sensory signals originating from the hand. To restore motor function with upper-limb neuroprostheses requires that somatosensory feedback be provided to the tetraplegic patient or amputee. Given the complexity of state-of-the-art prosthetic limbs, and thus the huge state-space they can traverse, it is desirable to minimize the need of the patient to learn associations between events impinging upon the limb and arbitrary sensations. With this in mind, we seek to develop approaches to intuitively convey sensory information that is critical for object manipulation – information about contact location, pressure, and timing – through intracortical microstimulation (ICMS) of primary somatosensory cortex (S1). To this end, we test in psychophysical experiments with monkeys, the sensations evoked by ICMS of S1. Based on these results, we show how to build a biomimetic encoding algorithm for conveying tactile feedback through a cortical interface and show that artificial touch improves the dexterity of brain-controlled bionic hands.

Davide Filingeri (4 July afternoon)

ThermosenseLab, Skin Sensing Research Group, School of Health Sciences, The University of Southampton, Southampton, UK

Wet, damp, moist, humid…what do we really feel? Thermo-tactile interactions in skin wetness sensing

We sweat during a run, and we feel wet. We grab the kitchen cloth, and it feels damp. We put on a body lotion and our skin feels moist. We step outside during a warm summer day in a Mediterranean island, and the air immediately feels humid. But how do these common sensory experiences arise in our brains, and what do we really “feel” when experiencing wetness, dampness, moistness, and humidity? Over the past 10 years, our research group has reported that wetness perceptions are a phenomenon of the central nervous system, resulting from higher-order neural structures integrating multisensory thermal (e.g. cold) and tactile (e.g. stickiness) inputs arising from the skin’s contact with moisture. Also, we have recently observed that the cold-sensing Transient Receptor Potential Melatstatin-8 (TRPM8) ion channel plays the dual role of cold and wetness receptor in human skin. Our findings have contributed to the development of an empirical neurophysiological model which helps explaining how, in the (apparent) absence of a skin hygroreceptor, healthy young adults may integrate thermal and tactile cues to perceive wetness on their skin. But how wetness sensing develops during childhood and potentially declines in later life, and how physiological and pathological changes in the perception of skin wetness across the lifespan impact on humans’ ability to interact with their surrounding environments, remains understudied. This talk will provide an overview of our group’s recent investigations on the mechanisms of human skin wetness sensing, and of its inter-individual variability, in both health and disease.

Rochelle Ackerley (5 July morning)

CNRS Researcher, Laboratoire de Neurosciences Cognitives, CNRS – Aix-Marseille University, Marseille, France

IASAT presidential lecture: The story of C-tactile (CT) afferents and their role in affective touch

Since their initial discovery in cats, low-threshold C-fiber mechanoreceptors, known as C-tactile (CT) afferents in humans, has captivated researchers over their properties and potential role in affective touch. We have been recording from CT afferents for over 30 years, yet only a handful of papers have described their characteristics. I will summarize these and extend our ideas on what we believe CTs to do. This ranges from their exquisite sensitivity to gentle stroking, through to their optimal activation at different temperatures. I will link this to perceptual studies using similar approaches and highlight what we know – and do not know – about the role of CTs in touch. Although CTs likely support gentle, positive affective touch encoding, affective touch is much more than this, as not every affective touch experience relies on CTs or must necessarily be pleasant.

Gary R. Lewin (5 July afternoon)

Photo by Pablo Catagnola

Molecular Physiology of Somatic Sensation Laboratory, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin-Buch, Germany.

Touch is really skin deep: cellular and molecular mechanisms of sensory mechanotransduction

Touch is one of the most sensitive, fastest and emotionally resonant of all our senses. The thrill of a brush of hair or the shock of an unseen spider web are both initiated by mechanoreceptors with high sensitivity and speed. In order to initiate such sensation sensory endings in the skin must be capable of detecting the tiniest of vibrations that can be in the nanometer range. Mechanically gated ion channels are the primary transducers of such forces and our work is focused on identifying these molecules and understanding how they achieve sensitivity and speed of sensory transduction. I will introduce two mechanically gated ion channels Piezo2 and Elkin1 which together may account for the majority of sensory transduction. However, recent work has indicated that we have to reevaluate the role of cells within the skin that form specialized end-organs innervated by the sensory mechanoreceptors e.g. Meissner’s corpuscles. I will present evidence that these cells play an integral part in sensing touch and tuning the sensitivity of skin mechanoreceptors. The start of touch is indeed only skin deep.

Ingvars Birznieks (6 July morning)

School of Medical Sciences, UNSW Sydney, Australia

Sense of touch and movement go hand in hand

The interdependence of movement and skin biomechanics determines tactile afferent signals which shape our perception and control our hand movements.  Friction is a key component of this process, as it is integral to any skin-surface interactions. In sense of touch friction has several functional contexts. When we explore the properties of different materials, we slide our fingers over the surface because movement enables skin mechanoreceptors to obtain a wealth of sensory information. Gentle caressing movements transmit social signals and emotions. In both circumstances, friction determines the tactile afferent response, and consequently may influence our perception and subjective attitude towards these stimuli. In motor control, knowledge of friction informs grip forces, so that the most fragile objects can be held without slipping or being crushed by excessive force. Our hands can also perform powerful actions such as rock climbing or using tools where friction and grip forces required to avoid slips set capability limits. Therefore, apart from automatic grip force adjustments, perception of slipperiness contributes to motor control by cognitive selection of a safe and achievable action plan. During object manipulation, sensing friction without exploratory rubbing movements is challenging. Our research has revealed that movement kinematics encompassing submillimeter range lateral movements may be sufficient to enable friction sensing. We have demonstrated this in psychophysics experiments, by biomechanical analyses, and during object manipulation. We have also shown tangential torque plays an important role. We demonstrate learning algorithms that extract these instantaneous stimulus parameters from afferent input, helping us to understand the neural code.

India Morrison (6 July afternoon)

Department of Biomedical and Clinical Sciences, Division of Neurobiology, Linköping University, Linköping, Sweden

The neuroscience of human social touch

Our knowledge of the neural underpinnings of affective touch has burgeoned over the past two decades, on levels from the receptor to larger-scale functional neuroanatomy of the brain. Yet we still understand very little about how these mechanisms might contribute to the role of touch in human social interaction. This talk outlines ways in which specific properties of touch can be organized by the human nervous system during affiliative social interactions. It examines candidate mechanisms for how the brain may integrate sensory features of human touch alongside contextual and “person-level” processes such as memory, expectation, and motivation. In particular, recent investigations of co-modulation between the brain and the neuropeptide oxytocin have suggested that oxytocin neuromodulation during touch-mediated social interactions is flexible and context-dependent. In humans, parietotemporal brain pathways may play a selective role in these context-sensitive processes, potentially allowing “tuning” of brain and body responses during social interactions. Such brain-hormone co-modulation during touch-mediated human social interactions allows for dynamic changes in interactants’ behavior and physiological states. These processes can serve not only in the formation and maintenance of affiliative relationships, but also in the body’s regulation of acute stress reactivity.  Looking to the future, these emerging lines of evidence foster a view of touch as a playing a temporal role in human interaction—unfurling not just during a single social interaction but over the course of a relationship.

Francis McGlone (7 July morning)
          

We were pleased to welcome Tiffany Field to our meeting, but unfortantely, she has had to cancel at the last minute. Francis McGlone has stepped in to deliver a tribute to Tiffany Field. As well as showing videos of Tiffany Field speaking about her decades of research in affective touch, Francis McGlone will present an overview of the vast contribution that Tiffany Field has made to our field and will then present a study of his that is based directly on Tiffany Field’s work, demonstrating its wide impact.