1,721,036 research outputs found
Supplementary material for the journal article 'Cutaneous thermosensory mapping of the female breast and pelvis - ESM'
No full textThis ESM contains 1 Excel file titled "Supplementary material for the journal article 'Cutaneous thermosensory mapping of the female breast and pelvis - ESM". The file contains statistical significance values for multiple skin location comparisons. This data is in support of the published paper "Cutaneous thermosensory mapping of the female breast and pelvis". Variations in thermal sensations were analyzed for the independent effects of skin location (17 levels) and thermal quality (2 levels, warm vs. cold stimulus) by means of two-way repeated measures ANOVA. To facilitate the comparison between warm and cold sensations, sensation data were transformed to fit a range of 0-100, where 0 corresponded to Neutral and 100 to Very Cold/Very Hot. In the event of statistically significant main effects or interactions, post hoc analyses were conducted with Sidak’s tests.</span
How hot is too hot for people? A review of empirical models of perceptual, physiological and functional limits of human heat tolerance
No full textHow hot is too hot for people? This is a question that human thermal physiologists are asked often by a variety of knowledge users across the public and private sectors, who have grown aware of the negative impact of global warming on people's health and quality of life. The aim of this paper is to provide a narrative review of models that quantify the limits of human heat tolerance across perceptual, physiological and functional domains. Several models exist that have identified critical environmental limits for heat tolerance across the perceptual, physiological and functional domains. However, no model is currently available that has evaluated all domains of heat tolerance concurrently and in the same participant cohort. Hence, by combining evidence from these models, here we propose a new holistic framework of heat tolerance that can help more comprehensively characterise the full spectrum of possible human responses to heat stress under free-living conditions. This framework highlights that human heat tolerance varies largely across the perceptual, physiological and functional domains, and that it is conceptually organised in line with the human body's ability to regulate body temperature via behavioural and autonomic responses. While our new framework presents limitations in its generalisability beyond healthy young adult cohorts, we hope that it will inspire the design of new holistic research on human heat tolerance in a broader range of participant cohorts, to better inform person-centred heat resilience policies and interventions that protect human health and life quality under a warming climate.</p
An evaluation of the effects of localised skin cooling on microvascular, inflammatory, structural, and perceptual responses to sustained mechanical loading of the sacrum: a study protocol: A study protocol
No full textThis study protocol aims to investigate how localised cooling influences the skin’s microvascular, inflammatory, structural, and perceptual tolerance to sustained mechanical loading at the sacrum, evaluating factors such as morphology, physiology, and perceptual responses. The protocol will be tested on individuals of different age, sex, skin tone and clinical status, using a repeated-measure design with three participants cohorts: i) young healthy (n=35); ii) older healthy (n=35); iii) spinal cord injured (SCI, n=35). Participants will complete three testing sessions during which their sacrum will be mechanically loaded (60 mmHg; 45 min) and unloaded (20 min) with a custom-built thermal probe, causing pressure-induced ischemia and post-occlusive reactive hyperaemia. Testing sessions will differ by the probe’s temperature, which will be set to either 38°C (no cooling), 24°C (mild cooling), or 16°C (strong cooling). We will measure skin blood flow (via Laser Doppler Flowmetry; 40 Hz); pro- and anti-inflammatory biomarkers in skin sebum (Sebutape); structural skin properties (Optical Coherence Tomography); and ratings of thermal sensation, comfort, and acceptance (Likert Scales); throughout the loading and unloading phases. Changes in post-occlusive reactive hyperaemia will be considered as the primary outcome and data will be analysed for the independent and interactive effects of stimuli’s temperature and of participant group on within- and between-subject mean differences (and 95% Confidence Intervals) in peak hyperaemia, by means of a 2-way mixed model ANOVA (or Friedman). Regression models will also be developed to assess the relationship between absolute cooling temperatures and peak hyperaemia. Secondary outcomes will be within- and between-subject mean changes in biomarkers’ expression, skin structural and perceptual responses. This analysis will help identifying physiological and perceptual thresholds for the protective effects of cooling from mechanically induced damage underlying the development of pressure ulcers in individuals varying in age and clinical status
The evolution of wetness perception: A comparison of arachnid, insect and human models
No full textHygroreceptors are a type of humidity sensor that have been identified in several invertebrate classes including Insecta and Arachnida. While their structure has been well researched, the nature of the mechanisms behind their function is debated as being either mechanical, evaporative, or psychrometric in insects and potentially also olfactory in arachnids. There is evidence that can be used to support or oppose each of these concepts, which also invites the possibility of multiple unified mechanisms occurring together. The integration of multiple sensory modalities has also formed the foundation of wetness perception in humans, led by thermal and tactile cues with supplementary information from vision and sound. These inputs are integrated by a vast neural network in the brain, which also occurs on a smaller scale in insects and arachnids. It is possible that as cerebral capacity increased throughout human evolution, this facilitated a preferable system of wetness perception via multisensory integration and rendered hygroreceptors obsolete. While this cerebral development hypothesis is only speculative, it gives a framework for further investigation. Additional research needs to be conducted to correctly classify hygroreceptor types in invertebrates and their relative prevalence before evolutionary associations can be made with vertebrate species. This integratory premise also applies to the human system, as knowing the relative contribution and compounding effects of each sensory modality on wetness perception will aid the overall understanding of the system and help to uncover the evolutionary development pathways underpinning each sense
Evidence for the involvement of peripheral cold-sensitive TRPM8 channels in human cutaneous hygrosensation
No full textIn contrast with other species, humans are believed to lack hygroreceptors for sensing skin wetness. Yet, the molecular basis of human hygrosensation are currently unknown and it remains unclear whether we possess a receptor-mediated sensing mechanism for skin wetness. The aim of this study was to assess the role of the cutaneous cold-sensitive Transient Receptor Potential Melatstatin-8 (TRPM8) channel as a molecular mediator of human hygrosensation. To this end, we exploited both the thermal and chemical activation of TRPM8-expressing cutaneous Aδ cold thermoreceptors and we assessed wetness sensing in healthy young males in response to 1) dry skin cooling in the TRPM8-range of thermosensitivity; 2) application of TRPM8-agonist menthol. Our results indicated that: 1) independently of contact with moisture, a cold-dry stimulus in the TRPM8-range of activation induced wetness perceptions across 12 different body regions, and those wetness perceptions varied across the body following regional differences in cold sensitivity; 2) independently of skin cooling, menthol-induced stimulation of TRPM8 triggered wetness perceptions that were greater than those induced by physical dry cooling and by contact with an aqueous cream containing actual moisture. For the first time, we show that the cutaneous cold-sensing TRPM8 channel plays the dual role of cold and wetness sensor in human skin and that this ion channel is a peripheral mediator of human skin wetness perception
Impact of Localised Skin Cooling at the Sacrum on Microvascular Responses to Sustained Pressure-induced Ischemia
No full text
Impact of localised skin cooling at the sacrum on microvascular responses to sustained pressure-induced ischemia
No full textSkin wetness detection thresholds and wetness magnitude estimations of the human index fingerpad and their modulation by moisture temperature
No full textHumans often experience wet stimuli using their hands, yet we know little on how sensitive our fingers are to wetness and the mechanisms underlying this sensory function. We therefore aimed to quantify the minimum amount of water required to detect wetness on the human index fingerpad, the wetness detection threshold, and assess its modulation by temperature. Eight blinded participants (24.0 ± 5.2 y; 23.3 ± 3.5 BMI) used their index fingerpad to statically touch stimuli varying in volume (0, 10, 20, 30, 40 or 50 ml) and temperature (25, 29, 33 or 37 °C). During and post contact, participants rated wetness and thermal sensations using a modified yes/no task and a visual analogue scale. The wetness detection threshold at a moisture temperature akin to human skin (33 °C) was 24.7 ± 3.2ml. This threshold shifted depending on moisture temperature (P = 0.002), with cooler temperatures reducing (18.7 ± 3.9ml at 29 °C) and warmer temperatures increasing (27.0 ± 3.0ml at 37 °C) thresholds. When normalised over contact area, the wetness detection threshold at 33 °C corresponded to 1.926x10-4 ml mm-2 (95% CI: 1.873x10-4, 1.979x10-4 ml mm-2). Threshold differences were reflected by magnitude estimation data, which were analysed using linear regression to show that both volume and moisture temperature can predict magnitude estimations of wetness (P < 0.001). Our results indicate high sensitivity to wetness in the human index fingerpad, which can be modulated by moisture temperature. These findings are relevant for the design of products with wetness management properties.</p
- …
