Gregory Gerling

Gregory Gerling
University of Virginia | UVa · Department of Systems and Information Engineering

PhD

About

118
Publications
16,486
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,427
Citations
Introduction
Gregory Gerling currently works at the School of Engineering and Applied Science at the University of Virginia. His work surrounds the interface of people and machines - focusing in particular on the sense of touch. His research interests are related to the fields of haptics, computational neuroscience, human factors and ergonomics, biomechanics, and human–machine interaction.
Additional affiliations
July 2011 - present
University of Virginia
Position
  • Professor (Associate)
August 2005 - June 2011
University of Virginia
Position
  • Professor (Assistant)
January 2001 - July 2005
University of Iowa
Position
  • PhD Student
Education
January 2002 - July 2005
University of Iowa
Field of study
  • Industrial Engineering

Publications

Publications (118)
Article
Full-text available
Touch is a powerful communication tool, but we have a limited understanding of the role played by particular physical features of interpersonal touch communication. In this study, adults living in Sweden performed a task in which messages (attention, love, happiness, calming, sadness, and gratitude) were conveyed by a sender touching the forearm of...
Article
Full-text available
Across a plethora of social situations, we touch others in natural and intuitive ways to share thoughts and emotions, such as tapping to get one’s attention or caressing to soothe one’s anxiety. A deeper understanding of these human-to-human interactions will require, in part, the precise measurement of skin-to-skin physical contact. Among prior ef...
Poster
Full-text available
Background and aims: In humans, all cutaneous A-beta afferents are considered to exclusively signal discriminative touch, whereas A-delta and C afferents signal pain. We recently identified A-beta high-threshold mechanoreceptors that encoded painful skin indentations and when selectively activated evoked painful percepts. We termed them “ultrafast...
Preprint
Full-text available
Across a plethora of social situations, we touch others in natural and intuitive ways to share thoughts and emotions, such as tapping to get one's attention or caressing to soothe one's anxiety. A deeper understanding of these human-to-human interactions will require, in part, the precise measurement of skin-to-skin physical contact. Among prior ef...
Preprint
Mechanosensory neurons in the mouth provide essential information to guide feeding and speech. How classes of oral mechanoreceptors contribute to oral behaviors is not well understood; in particular, the functional properties of lingual mechanoreceptors remain elusive. Previous work identified putative mechanosensory endings in the tongue with nove...
Preprint
Full-text available
We routinely communicate distinct social and emotional sentiments through nuanced touch. For example, we might gently hold another's arm to offer a sense of calm, yet intensively hold another's arm to express excitement or anxiety. As this example indicates, distinct sentiments may be shaped by the subtlety in one's touch delivery. This work invest...
Article
Thin von Frey monofilaments are a clinical tool used worldwide to assess touch deficits. Ones ability to perceive touch with low-force monofilaments (0.008 0.07 g) establishes an absolute threshold and thereby the extent of impairment. While individual monofilaments bend at defined forces, there are no empirical measurements of the skin surfaces re...
Article
We routinely communicate distinct social and emotional sentiments through nuanced touch. For example, we might gently hold anothers arm to offer a sense of calm, yet intensively hold anothers arm to express excitement or anxiety. As this example indicates, distinct sentiments may be shaped by the subtlety in ones touch delivery. This work investiga...
Preprint
Full-text available
Touch is a powerful communication tool, but we have a limited understanding of the role played by particular physical features of interpersonal touch communication. In this study, adults living in Sweden performed a task in which messages (attention, love, happiness, calming, sadness and gratitude) were conveyed by a sender touching the forearm of...
Article
Full-text available
Search and rescue missions are time-sensitive, with their duration impacting survivability. Unmanned aerial vehicles (UAVs) are increasingly shortening response time, accelerating area coverage, and informing resource allocation. However, interactions of UAVs and human operators pose challenges, for example, related to understandability and trust i...
Conference Paper
Brushed stimuli are perceived as pleasant when stroked lightly on the skin surface of a touch receiver at certain velocities. While the relationship between brush velocity and pleasantness has been widely replicated, we do not understand how resultant skin movements - e.g., lateral stretch, stick-slip, normal indentation - drive us to form such jud...
Conference Paper
Tactile acuity differs between individuals, likely a function of several interrelated factors. The extent of the impact of skin mechanics on individual differences is unclear. Herein, we investigate if differences in skin elasticity between individuals impact their ability to distinguish compliant spheres near limits of discriminability. After char...
Conference Paper
Full-text available
Individual differences in tactile acuity are observed within and between age cohorts. Such differences in acuity may be attributed to various sources, including aspects of nervous system, skin mechanics, finger size, cognitive and behavioral factors, etc. This work considers individual differences, within a younger cohort of participants, in discri...
Article
Full-text available
Our sense of touch helps us encounter the richness of our natural world. Across a myriad of contexts and repetitions, we have learned to deploy certain exploratory movements in order to elicit perceptual cues that are salient and efficient. The task of identifying optimal exploration strategies and somatosensory cues that underlie our softness perc...
Preprint
Full-text available
Our sense of touch helps us encounter the richness of our natural world. Across a myriad of contexts and repetitions, we have learned to deploy certain exploratory movements in order to elicit perceptual cues that are optimal and efficient. Such cues help us assess an object's roughness, or stickiness, or as in this case, its softness. Leveraging e...
Conference Paper
Full-text available
We regularly touch soft, compliant fruits and tissues. To help us discriminate them, we rely upon cues embedded in spatial and temporal deformation of finger pad skin. However, we do not yet understand, in touching objects of various compliance, how such patterns evolve over time, and drive perception. Using a 3-D stereo imaging technique in passiv...
Conference Paper
Our perception of compliance is informed by multi-dimensional tactile cues. Compared with stationary cues at terminal contact, time-dependent cues may afford optimal efficiency, speed, and fidelity. In this work, we investigate strategies by which temporal cues may encode compliances by modulating our exploration time. Two potential perceptual stra...
Conference Paper
Full-text available
Touch interaction cues help inform our sense of compliance. Efforts to ascertain the most relevant cues are mostly done with materials such as silicone-elastomers, foams, and robotic devices. It is unclear how well these engineered substances approximate the intrinsic material properties of ecologically compliant objects. Herein we study human tact...
Conference Paper
We employ distinct exploratory procedures to improve our perceptual judgments of an object’s properties. For instance, with respect to compliance, we exert pressure against a resisting force. The present work investigates ties between strategies for active control of the finger and resultant cues by which compliances may be discriminated. In partic...
Conference Paper
Full-text available
Human-to-human touch conveys rich, meaningful social and emotional sentiment. At present, however, we understand neither the physical attributes that underlie such touch, nor how the attributes evoke responses in unique types of peripheral afferents. Indeed, nearly all electrophysiological studies use well-controlled but non-ecological stimuli. Her...
Conference Paper
Full-text available
Couples often communicate their emotions, e.g., love or sadness, through physical expressions of touch. Prior efforts have used visual observation to distinguish emotional touch communications by certain gestures tied to one's hand contact, velocity and position. The work herein describes an automated approach to eliciting the essential features of...
Article
Full-text available
Differentiation between self-produced tactile stimuli and touch by others is necessary for social interactions and for a coherent concept of “self.” The mechanisms underlying this distinction are unknown. Here, we investigated the distinction between self- and other-produced light touch in healthy volunteers using three different approaches: fMRI,...
Article
In our ability to discriminate compliant, or ‘soft,’ objects, we rely upon information acquired from interactions at the finger pad. We have yet to resolve the most pertinent perceptual cues. However, doing so is vital for building effective, dynamic displays. By introducing psychophysical illusions through spheres of various size and elasticity, w...
Article
Full-text available
Distinct firing properties among touch receptors are influenced by multiple, interworking anatomical structures. Our understanding of the functions and crosstalk of Merkel cells and their associated neurites—the end organs of slowly adapting type I (SAI) afferents—remains incomplete. Piezo2 mechanically activated channels are required both in Merke...
Data
Model produced instantaneous firing frequencies under a parameter sweep with computational model, low magnitude of stimulation, wildtype case. Panels A—C show IFFs when the generator function is run in the context of the entire end organ model. These correspond to the parameter modifications to generate the currents in Fig 3, panels D—F. The tau va...
Data
The parameters τSI and τRI, respectively, of the generator function are fitted from recording data. In particular, panel (A) shows a characteristic trace of in vitro Merkel cell membrane potential over time under a current clamped prep, delivered a step mechanical stimulus at about 88% of the saturation threshold, and panel (B) shows a characterist...
Data
To accompany the low magnitude stimulus example in Fig 3C, shown here is the high magnitude stimulus case, likewise showing the need for the USI component. Without the USI component, the output IFF reaches a plateau and does not adapt as is typically observed for SAI afferents. (TIF)
Data
Time course of IFF decay observed in neural recordings cannot be achieved by skin viscoelasticity alone in absence of USI current. In Panel A, three computational simulations were run where the skin’s viscoelasticity was varied by changing G∞ from 0.81, 0.35, and 0.10 for a 418 micron thick skin in the finite element model. The range of relaxation...
Article
Understanding how we perceive differences in material compliance, or ‘softness,’ is a central topic in the field of haptics. The intrinsic elasticity of an object is the primary factor thought to influence our perceptual estimates. Therefore, most studies test and report the elasticity of their stimuli, typically as stiffness or modulus. However, m...
Conference Paper
Full-text available
We need to understand the physics of how the skin of the finger pad deforms, and their tie to perception, to accurately reproduce a sense of compliance, or 'softness,' in tactile displays. Contact interactions with compliant materials are distinct from those with rigid surfaces where the skin flattens completely. To capture unique patterns in skin...
Conference Paper
Full-text available
In mammals, touch is encoded by sensory receptors embedded in the skin. For one class of receptors in the mouse, the architecture of its Merkel cells, unmyelinated neurites, and heminodes follow particular renewal and remodeling trends over hair cycle stages from ages 4 to 10 weeks. As it is currently impossible to observe such trends across a sing...
Article
Grasping and manipulating an object requires us to perceive its material compliance. Compliance is thought to be encoded by relationships of force, displacement and contact area at the finger pad. Prior work suggests that objects must be sufficiently deformed to become discriminable, but the utility of time-dependent cues has not been fully explore...
Article
Full-text available
Sensory tissues exposed to the environment, such as skin, olfactory epithelia, and taste buds, continuously renew; therefore, peripheral neurons must have mechanisms to maintain appropriate innervation patterns. Although somatosensory neurons regenerate after injury, little is known about how these neurons cope with normal target organ changes. To...
Article
The papers in this special section is to focus on the deployment of haptics in the field of neuroscience. The neuroscience of haptics has made many breakthroughs over the last six or so decades and these scientific advances are now being leveraged to develop new therapies for patients suffering from sensorimotor disorders and new technologies to im...
Article
Full-text available
In order to accelerate implementation of hyperelastic materials for finite element analysis, we developed an automatic numerical algorithm that only requires the strain energy function. This saves the effort on analytical derivation and coding of stress and tangent modulus, which is time-consuming and prone to human errors. Using the one-sided Newt...
Article
Distinct patterns in neuronal firing are observed between classes of cutaneous afferents. Such differences may be attributed to end organ morphology, distinct ion-channel complements, and skin microstructure, among other factors. Even for just the slowly adapting type I afferent, the skin’s mechanics for a particular specimen might impact the affer...
Conference Paper
Full-text available
Distinct patterns in neuronal firing are observed between classes of cutaneous afferents. Similarly, differences in sensitivity are observed within a class of afferents, e.g., slowly adapting type I afferents. Given the dramatic changes in skin thickness and elasticity that are observed in the mouse due to normal skin remodeling, one could speculat...
Conference Paper
Full-text available
Distinguishing an object's compliance, into percepts of "softness" and "hardness," is crucial to our ability to grasp and manipulate it. Biomechanical cues at the skin's surface such as contact area and force rate have been thought to help encode compliance. However, no one has directly measured contact area with compliant materials, and few studie...
Conference Paper
The information that emergency medical technicians (EMTs) collect at the incident site is typically communicated verbally to the emergency department (ED) prior to arrival. However, communication by verbal channels can introduce lags, is limited by human recall and attention, is repetitious, and often lacks consistent and sufficient detail. To fill...
Article
To combat the risk of hyperglycemia while in the hospital, a patient's insulin delivery should be correlated with blood glucose levels and meal consumption. At present, there is a particularly acute disconnect between insulin delivery and meal consumption. There are simply no formal processes for communicating the status of meal delivery, and there...
Article
Each year, approximately 185,000 Americans suffer the devastating loss of a limb. The effects of upper limb amputations are profound because a person's hands are tools for everyday functioning, expressive communication, and other uniquely human attributes. Despite the advancements in prosthetic technology, current upper limb prostheses are still li...
Article
Full-text available
Although the skin's mechanical properties are well characterized in tension, little work has been done in compression. Here, the viscoelastic properties of a population of mouse skin specimens (139 samples from 36 mice, aged 5 to 34 weeks) were characterized upon varying specimen thickness, as well as strain level and rate. Over the population, we...
Article
Full-text available
Background To identify the impact of weight, table surface, and table type on slipping in a simulation of minimally invasive gynecologic surgery. Methods A mannequin was placed into increasing Trendelenburg until a slip was observed; the table angle at the time of the event was measured (slip angle). The influence of mannequin position (supine vs....
Conference Paper
Full-text available
Our capability to discriminate object compliance is based on cues both tactile and proprioceptive, in addition to visual. To understand how the mechanics of the fingertip skin and bone might encode such information, we used finite element models to simulate the task of differentiating spherical indenters of radii (4, 6 and 8 mm) and elasticity (ini...
Article
Full-text available
Previous models of touch have linked skin mechanics to neural firing rate, neural dynamics to action potential elicitation, and mechanoreceptor populations to psychophysical discrimination. However, no one model spans all levels. The objective of work herein is to build a multi-level, computational model of tactile neurons embedded in cutaneous ski...
Conference Paper
Full-text available
In effort to mimic the sensitivity and efficient information transfer of natural tactile afferents, recent work has combined force transducers and computational models of mechanosensitive afferents. Sensor durability, another feature important to sensor design, might similarly capitalize upon biological rules. In particular, gains in sensor durabil...
Conference Paper
When afférents reinnervate the muscle tissue nearby a stimulating electrode, it is hard to control how well the single stimulating site of the electrode aligns physically with the location of the nerve fiber. To account for such issues in positioning, a multi-site electrode might aid by delivering electrical stimulation in a distributed fashion. In...
Article
The sense of touch, and the neural code that underlies it, makes it possible to execute everyday tasks such as picking up a glass or buttoning a shirt. Recreating touch in upper limb prostheses requires an in-depth understanding of how indentation of the skin is transformed to the time of occurrence of neural action potentials by tactile mechanorec...
Article
Full-text available
Clinical breast examinations (CBE) play a role in the detection of breast cancers. However, most physicians receive inadequate training in tactile search of breast tissue to detect small (< 2 cm), hard tumors. The dynamic, variable-lump, silicone breast simulator was designed to improve physicians' CBE performance and increase tumor detection. Wate...
Article
Full-text available
The skin is a dynamic organ whose complex material properties are capable of withstanding continuous mechanical stress while accommodating insults and organism growth. Moreover, synchronized hair cycles, comprising waves of hair growth, regression and rest, are accompanied by dramatic fluctuations in skin thickness in mice. Whether such structural...
Conference Paper
Full-text available
The neural response to touch stimuli is influenced by skin properties as well as the delivery of stimuli. Here, we compare stimuli controlled by displacement and force, and analyze the impact on firing rates of slowly adapting type I afferents as skin thickness and elasticity change. Uniaxial compression tests were used to measure the mechanical pr...
Conference Paper
Hip dislocations are rare events. As a consequence, medical residents have little opportunity to gain experience through repeated practice. In fact, little is known about the forces and displacements that experienced physicians employ during the procedure. This study seeks to quantify the strategic maneuvering and substantial force required to repo...