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Spatial acuity of the nipple and areola. A| Test locations for the quadrant discrimination task. The subject reported location using a number from 1 to 4 progressing clockwise from "above." B| Proportion correct localization. (N=10)
Source publication
A bstract
The sense of touch plays a key role in our experience of our body and our interactions with the world, from the objects we manipulate to the people we touch. While tactile sensibility and its neural basis have been extensively characterized for the glabrous skin of the hand, much less is known about touch on other parts of the body. Despi...
Contexts in source publication
Context 1
... nipple is a unit STs obtained from the medial breast are difficult to interpret because they reflect judgments about three anatomically distinct regions of the breast: the nipple, the areola, and the nearby outer breast. To assess the acuity within the nipple and areola separately, we delivered a punctate touch to a location at one of four quadrants on the nipple or areola and the subject reported the quadrant in which the touch had been delivered ( Figure 2A). We could then assess the degree to which different regions of these breast components were distinguishable from one another. ...
Context 2
... one outlier systematically misperceived the location. Subjects performed even more poorly in identifying the quadrant of a touch on the nipple, with only five out of ten achieving above chance performance ( Figure 2B). In other words, while touches to different parts are somewhat distinguishable, the nipple is a sensory unit with little to no differentiation. ...
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... we investigated whether the bias was significantly greater than would be expected by chance. To this end, we allocated to each error a random angle around the actual location and recomputed the bias and imprecision for these simulated data ( Supplementary Figure 2), which reflect the level of bias and imprecision one would expect if all errors were simply due to imprecision. We found that the measured bias was significantly greater than its simulated counterpart ( Figure 3D), demonstrating that the perceived location of a touch on the breast was systematically biased. ...
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... objective of this experiment was to assess the degree to which women can distinguish touches to different parts of their NAC. On each trial, the subject was touched at one four locations on the nipple or areola (organized in a quadrant) and verbally identified the touch location using a number from 1 to 4 ( Figure 2A). Each location was touched ten times per block (40 trials per block, with 80 total trials per breast region). ...
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... the areola, each touch was located halfway between the edge of the areola and the nipple. For the nipple, each touch was delivered at the edge of the nipple, in line with each point on the areola (Figure 2A). The testing side was chosen randomly for each subject (6 left/4 right). ...
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... /2022 Supplementary Figure 2. Monte Carlo simulations of bias and imprecision for the breast and the back. ...
Context 7
... nipple is a unit STs obtained from the medial breast are difficult to interpret because they reflect judgments about three anatomically distinct regions of the breast: the nipple, the areola, and the nearby outer breast. To assess the acuity within the nipple and areola separately, we delivered a punctate touch to a location at one of four quadrants on the nipple or areola and the subject reported the quadrant in which the touch had been delivered ( Figure 2A). We could then assess the degree to which different regions of these breast components were distinguishable from one another. ...
Context 8
... one outlier systematically misperceived the location. Subjects performed even more poorly in identifying the quadrant of a touch on the nipple, with only five out of ten achieving above chance performance ( Figure 2B). In other words, while touches to different parts are somewhat distinguishable, the nipple is a sensory unit with little to no differentiation. ...
Context 9
... we investigated whether the bias was significantly greater than would be expected by chance. To this end, we allocated to each error a random angle around the actual location and recomputed the bias and imprecision for these simulated data ( Supplementary Figure 2), which reflect the level of bias and imprecision one would expect if all errors were simply due to imprecision. We found that the measured bias was significantly greater than its simulated counterpart ( Figure 3D), demonstrating that the perceived location of a touch on the breast was systematically biased. ...
Context 10
... objective of this experiment was to assess the degree to which women can distinguish touches to different parts of their NAC. On each trial, the subject was touched at one four locations on the nipple or areola (organized in a quadrant) and verbally identified the touch location using a number from 1 to 4 ( Figure 2A). Each location was touched ten times per block (40 trials per block, with 80 total trials per breast region). ...
Context 11
... the areola, each touch was located halfway between the edge of the areola and the nipple. For the nipple, each touch was delivered at the edge of the nipple, in line with each point on the areola (Figure 2A). The testing side was chosen randomly for each subject (6 left/4 right). ...
Citations
... Regional differences to light touch within the breast exist, yet their intensity patterns vary with the menstrual cycle, following childbirth [7] and with breast size [9]. Furthermore, breast acuity to light touch has been recently shown to be poorer compared to other regions of the body (i.e. the hand and the back) with no differences detected between the outer and the medial breast [10]. Regarding differences in light touch sensitivity between the breast and pelvis, Cordeau et al. have shown that the vaginal margin has lower detection thresholds for light touch than the areola [11]. ...
Humans are not provided with humidity receptors and the ability to perceive skin wetness seems to rely on the sensory inputs arising from thermal cold afferents. Given the regional variability in thermal sensitivity across the torso, we examined whether regional differences in the sensitivity to wetness exist. Sixteen male participants were tested at rest. Twelve regions of the torso were stimulated with a dry or wet thermal probe (25cm²) set at a temperature of 15°C below the local skin temperature, which was measured pre and post stimulation. Thermal and wetness sensations were recorded using likert scales. As a result of the same relative cold stimuli, the skin cooling response varied by location and regional differences were found in thermal and wetness sensations. The lateral chest showed the greater drop in local skin temperature. Colder sensations were reported on the lateral abdomen and lower back. Greater wetness was reported on the lower back. No differences were perceived between wet and dry stimuli, the dry ones perceived as wet as the wet ones. The regional variability in wetness sensitivity showed a pattern similar to the thermal sensitivity to cold. We conclude that, as thermal cold afferents seem to have a critical role in driving the perception of wetness, based on the regional variability in thermal sensitivity, humans present regional differences in the cutaneous sensitivity to wetness across the torso.
Grant Funding Source : Supported by Loughborough University and Oxylane Research
Differences in skin thermal sensitivity have been extensively mapped across areas of the human body, including the torso, limbs, and extremities. Yet, there are parts of the female body, such as the breast and the pelvis for which we have limited thermal sensitivity data. The aim of this study was to map cutaneous warm and cold sensitivity across skin areas of the breast and pelvis that are commonly covered by female underwear. Twelve young females (21.9±3.2 years) reported on a 200-mm visual analogue scale the perceived magnitude of local thermal sensations arising from short-duration (10s) static application of a cold [5°C below local skin temperature (Tsk)] or warm (5°C above local Tsk) thermal probe (25cm2) in seventeen locations over the breast and pelvis regions. The data revealed that thermal sensitivity to the warm probe, but not the cold probe, varied by up to 25% across the breast [mean difference between lowest and highest sensitivity location was 51mm (95% CI:14, 89; p<0.001)] and up to 23% across the pelvis [mean difference between lowest and highest sensitivity location: 46mm (95% CI:9, 84; p=0.001)]. The regional differences in baseline Tsk did not account for variance in warm thermal sensitivity. Inter-individual variability in thermal sensitivity ranged between 24 and 101% depending on skin location. We conclude that the skin across the female breast and pelvis presents a heterogenous distribution of warm, but not cold, thermal sensitivity. These findings may inform the design of more comfortable clothing that are mapped to the thermal needs of the female body.
