scholarly journals Tactile innervation densities across the whole body

2020 ◽  
Vol 124 (4) ◽  
pp. 1229-1240
Author(s):  
Giulia Corniani ◽  
Hannes P. Saal

The skin is our largest sensory organ and innervated by afferent fibers carrying tactile information to the spinal cord and onto the brain. The density with which different classes of tactile afferents innervate the skin is not constant but varies considerably across different body regions. However, precise estimates of innervation density are only available for some body parts, such as the hands, and estimates of the total number of tactile afferent fibers are inconsistent and incomplete. Here we reconcile different estimates and provide plausible ranges and best estimates for the number of different tactile fiber types innervating different regions of the skin, using evidence from dorsal root fiber counts, microneurography, histology, and psychophysics. We estimate that the skin across the whole body of young adults is innervated by ∼230,000 tactile afferent fibers (plausible range: 200,000–270,000), with a subsequent decrement of 5–8% every decade due to aging. Fifteen percent of fibers innervate the palmar skin of both hands and 19% the region surrounding the face and lips. Slowly and fast-adapting fibers are split roughly evenly, but this breakdown varies with skin region. Innervation density correlates well with psychophysical spatial acuity across different body regions, and, additionally, on hairy skin, with hair follicle density. Innervation density is also weakly correlated with the size of the cortical somatotopic representation but cannot fully account for the magnification of the hands and the face.

Author(s):  
Giulia Corniani ◽  
Hannes P. Saal

The skin is our largest sensory organ and innervated by afferent fibers carrying tactile information to the spinal cord and onto the brain. The density with which different classes of tactile afferents innervate the skin is not constant but varies considerably across different body regions. However, precise estimates of innervation density are only available for some body parts, such as the hands, and estimates of the total number of tactile afferent fibers are inconsistent and incomplete. Here we reconcile different estimates and provide plausible ranges and best estimates for the number of different tactile fiber types innervating different regions of the skin, using evidence from dorsal root fiber counts, microneurography, histology, and psychophysics. We estimate that the skin across the whole body is innervated by approximately 230,000 tactile afferent fibers (plausible range: 200,000-270,000). 15% innervate the palmar skin of both hands and 19% the region surrounding the face and lips. Around 60% of all tactile fibers are slowly-adapting, while the rest are fastadapting. Innervation density correlates well with psychophysical spatial acuity across different body regions, and additionally, on hairy skin, with hair follicle density. Innervation density is also weakly correlated with the size of the cortical somatotopic representation, but cannot fully account for the magnification of the hands and the face.


Healthcare ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 33
Author(s):  
Norbert Hosten ◽  
Robin Bülow ◽  
Henry Völzke ◽  
Martin Domin ◽  
Carsten Oliver Schmidt ◽  
...  

The Study of Health in Pomerania (SHIP), a population-based study from a rural state in northeastern Germany with a relatively poor life expectancy, supplemented its comprehensive examination program in 2008 with whole-body MR imaging at 1.5 T (SHIP-MR). We reviewed more than 100 publications that used the SHIP-MR data and analyzed which sequences already produced fruitful scientific outputs and which manuscripts have been referenced frequently. Upon reviewing the publications about imaging sequences, those that used T1-weighted structured imaging of the brain and a gradient-echo sequence for R2* mapping obtained the highest scientific output; regarding specific body parts examined, most scientific publications focused on MR sequences involving the brain and the (upper) abdomen. We conclude that population-based MR imaging in cohort studies should define more precise goals when allocating imaging time. In addition, quality control measures might include recording the number and impact of published work, preferably on a bi-annual basis and starting 2 years after initiation of the study. Structured teaching courses may enhance the desired output in areas that appear underrepresented.


2008 ◽  
Vol 105 (6) ◽  
pp. 1897-1906 ◽  
Author(s):  
Mayumi Nakamura ◽  
Tamae Yoda ◽  
Larry I. Crawshaw ◽  
Saki Yasuhara ◽  
Yasuyo Saito ◽  
...  

Sensations evoked by thermal stimulation (temperature-related sensations) can be divided into two categories, “temperature sensation” and “thermal comfort.” Although several studies have investigated regional differences in temperature sensation, less is known about the sensitivity differences in thermal comfort for the various body regions. In the present study, we examined regional differences in temperature-related sensations with special attention to thermal comfort. Healthy male subjects sitting in an environment of mild heat or cold were locally cooled or warmed with water-perfused stimulators. Areas stimulated were the face, chest, abdomen, and thigh. Temperature sensation and thermal comfort of the stimulated areas were reported by the subjects, as was whole body thermal comfort. During mild heat exposure, facial cooling was most comfortable and facial warming was most uncomfortable. On the other hand, during mild cold exposure, neither warming nor cooling of the face had a major effect. The chest and abdomen had characteristics opposite to those of the face. Local warming of the chest and abdomen did produce a strong comfort sensation during whole body cold exposure. The thermal comfort seen in this study suggests that if given the chance, humans would preferentially cool the head in the heat, and they would maintain the warmth of the trunk areas in the cold. The qualitative differences seen in thermal comfort for the various areas cannot be explained solely by the density or properties of the peripheral thermal receptors and thus must reflect processing mechanisms in the central nervous system.


2020 ◽  
Vol 30 (11) ◽  
pp. 6051-6068 ◽  
Author(s):  
Adolfo M García ◽  
Eugenia Hesse ◽  
Agustina Birba ◽  
Federico Adolfi ◽  
Ezequiel Mikulan ◽  
...  

Abstract In construing meaning, the brain recruits multimodal (conceptual) systems and embodied (modality-specific) mechanisms. Yet, no consensus exists on how crucial the latter are for the inception of semantic distinctions. To address this issue, we combined electroencephalographic (EEG) and intracranial EEG (iEEG) to examine when nouns denoting facial body parts (FBPs) and nonFBPs are discriminated in face-processing and multimodal networks. First, FBP words increased N170 amplitude (a hallmark of early facial processing). Second, they triggered fast (~100 ms) activity boosts within the face-processing network, alongside later (~275 ms) effects in multimodal circuits. Third, iEEG recordings from face-processing hubs allowed decoding ~80% of items before 200 ms, while classification based on multimodal-network activity only surpassed ~70% after 250 ms. Finally, EEG and iEEG connectivity between both networks proved greater in early (0–200 ms) than later (200–400 ms) windows. Collectively, our findings indicate that, at least for some lexico-semantic categories, meaning is construed through fast reenactments of modality-specific experience.


2021 ◽  
Author(s):  
Elena Amoruso ◽  
Devin B. Terhune ◽  
Maria Kromm ◽  
Stephen Kirker ◽  
Dollyane Muret ◽  
...  

ABSTRACTBackground and ObjectivesTactile sensations referred to body parts other than those stimulated have been repeatedly described across a wide range of deafferentation and neuropathic pain conditions, including amputation, complex regional pain syndrome, spinal cord injury, and brachial plexus avulsion. Common to all interpretations of referred sensations is the notion that they result from central nervous system (CNS) reorganisation. For example, in amputees, sensations referred to the phantom limb following touches on the face have been classically interpreted as the perceptual correlate of cortical remapping of the face into the neighbouring missing-hand territory in primary somatosensory cortex (S1). Here, using the prominent model of acquired upper-limb amputation, we investigated whether referred sensations reports are associated with cortical remapping or can instead be attributed to demand characteristics (e.g., compliance, expectation, and suggestion), which have been shown to greatly influence self-reports of bodily sensations and were uncontrolled in previous assessments.MethodsUnilateral upper-limb amputees (N=18), congenital one-handers (N=19), and two-handers (N=20) were repeatedly stimulated with PC-controlled vibrations on ten body-parts and asked to report on each trial the occurrence of any concurrent sensations on their hand(s). To further manipulate expectations, we gave participants the suggestion that some of these vibrations had a higher probability to evoke referred sensations. To evaluate remapping, we analysed fMRI data in S1 from two tasks involving movement of facial and whole-body parts, using univariate and multivariate approaches.ResultsThe frequency and distribution of reported referred sensations were similar across groups, with higher frequencies in the high expectancy condition. In amputees, referred sensations were evoked by stimulation of multiple body-parts and reported in both the intact and phantom hand. The group profiles for referred sensations reports were not consistent with the observed patterns of S1 remapping.DiscussionThese findings weaken the interpretation of referred sensations as a perceptual consequence of post-deafferentation CNS reorganisation and reveal the need to account for demand characteristics when evaluating self-reports of anomalous perceptual phenomena for both research and clinical assessments purposes.


Author(s):  
Kalev Kuklane ◽  
Róbert Toma ◽  
Rebekah A.I. Lucas

Many workers are exposed to heat stress that can be exacerbated by the type of clothing they wear. The resulted heat strain can lead to short or long-term heat-related disorders. This study aimed to measure clothing properties of sugarcane field workers and evaluate the heat strain by an international standard, predicted heat strain model (PHS). The clothing thermal insulation and evaporative resistance values of sugarcane cutter and chemical sprayer outfits were acquired for the whole body, body regions and specific body parts via thermal manikin measurements. The detailed clothing insulation values of body parts can be utilized in advanced thermo-physiological models, while in this study, the values for the whole body together with weather data were used in PHS. Estimated duration limited exposure times (DLE) for an hour-by-hour prediction over a workday and for a range of high humidity scenarios were calculated. Such evaluation tools can be used for risk assessment and management to support organizational measures and prepare equipment and materials in the case of hot weather events in order to avoid dehydration and other heat-related disorders.


2010 ◽  
Vol 104 (3) ◽  
pp. 1484-1496 ◽  
Author(s):  
Sung Soo Kim ◽  
Arun P. Sripati ◽  
Sliman J. Bensmaia

What does the hand tell the brain? Tactile stimulation of the hand evokes remarkably precise patterns of neural activity, suggesting that the timing of individual spikes may convey information. However, many aspects of the transformation of mechanical deformations of the skin into spike trains remain unknown. Here we describe an integrate-and-fire model that accurately predicts the timing of individual spikes evoked by arbitrary mechanical vibrations in three types of mechanoreceptive afferent fibers that innervate the hand. The model accounts for most known properties of the three fiber types, including rectification, frequency-sensitivity, and patterns of spike entrainment as a function of stimulus frequency. These results not only shed light on the mechanisms of mechanotransduction but can be used to provide realistic tactile feedback in upper-limb neuroprostheses.


1984 ◽  
Vol 29 (7) ◽  
pp. 567-568
Author(s):  
Gilles Kirouac
Keyword(s):  
The Face ◽  

1987 ◽  
Vol 26 (05) ◽  
pp. 202-205 ◽  
Author(s):  
J. Fass ◽  
S. Truong ◽  
U. Büll ◽  
V. Schumpelick ◽  
R. Bares

Radioimmunoscintigraphy (RIS) with 111ln- and 131 I-labelled monoclonal anti bodies (MAbs) against CEA and/or CA 19-9 was performed in 83 patients with various gastrointestinal carcinomas. A total of 276 body regions could be examined. The results of planar scintigraphy and SPECT were compared intraindividually. Using 111 In-labelled MAbs the sensitivity of RIS was significantly improved by SPECT (88.9 vs. 52.4% with planar scintigraphy, p <0.01). For131 l-labelled MAbs the effect was smaller (83.9 vs. 65.6% with planar scintigraphy, n.s.). This finding can be explained by different kinetics and biodistribution of the used MAb preparations.111 In-labelled MAbs with long whole-body retention and rapid blood clearance reveal ideal qualities for SPECT; on the other hand, the short whole-body retention of131 l-labelled MAbs leads to small count rates and therefore long counting times that make delayed SPECT unsuitable in clinical practice


Horizons ◽  
2021 ◽  
Vol 48 (1) ◽  
pp. 172-194
Author(s):  
Christopher Pramuk

In March 1943, having narrowly escaped Europe three years earlier, Abraham Joshua Heschel published “The Meaning of This War,” his first essay in an American publication. The essay shows, quite remarkably, his full command of literary English. It also shows, as biographer Edward Kaplan remarks, that Heschel “had found his militant voice.” “Emblazoned over the gates of the world in which we live,” the essay begins, “is the escutcheon of the demons. The mark of Cain in the face of man has come to overshadow the likeness of God. There have never been so much guilt and distress, agony and terror. At no time has the earth been so soaked with blood.” Heschel's extraordinary life's witness, his whole body of work, traverses precisely this anthropological and theological knife's edge: The mark of Cain in the face of man has come to overshadow the likeness of God. Where is God? Or better, Who is God? in relation to the rapacious misuse and idolatrous distortion of human freedom? Or simply, Is God?


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